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#1071310 - 07/10/21 06:03 AM Why now, A/C R&R  
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mmc427ss Offline
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Of course during the heat of the Summer when you need the A/C in the car it lets you down. Last month on the return trip from Carlisle at 70+ for an hour and a half noticed my feet weren't frozen on the ride home. Didn't think much of that until a week later on a 95 degree day, dash vent weren't spitting ice cubes like the 13 years previous. In Aug will be putting 700 miles of highway driving so that needed to be addressed.

The car is an R12 stock system that a complete 100% R&R was done to when the new engine went in. It could easily keep up on the hottest of days. When the original compressor failed 20 years a complete 134 swap was done and was never happy with the 134 conversion. Thus all remnants on the 134 were purged from the system and a fresh R12 system was installed to compliment the new engine.

the other day put the gauges on the system and yep something is wrong, pressures way off. The compressor belt has a slight slap which it never had. Thinking the compressor has gone south, contaminated the orifice valve restricting flow. Removed the belt and turned the compressor over with a socket/ratchet and you can feel it's not right.
Next is evacuate the system and see if the compressor feels any different with no pressure on the system. Pull the orifice valve and look for junk on the screen. That is usually a good indication of compressor failing and contaminating the system.

Now need to find parts, the real problems begins, availability. Orifice valves no problem. An accumulator always get replaced when a system get opened for parts replacement. That part is specific to the car, at this point don't think I will have a problem getting the correct one. Compressor, will only install a new one, no rebuilt. Although it appears there are some supplier choices available that means nothing to what is actually on the shelf. Would like to stay Delco, Delphi, USA but looks like "imported" is what you get.

Always thought an upgrade to a parallel flow condenser was going to be done when the system needed to be repaired down the road. Well now at that point in the road and condensers are hard to find in any shape or form to fit our cars. Not long ago parallel condensers that were a drop in for a stock system were available. Today it's hard to find even a stock tube/fin replacement. Even a stock replacement Spectra Products 7-3232 is hard to come by, it's not a parallel.

Called ACKits, https://www.ackits.com/ on Thurs and had a long conversation with Tim the owner discussing ever aspect of my system. He can get me a compressor to bolt in. He made a few calls to see if he could get me a stock configuration parallel condenser from any of his suppliers, and to see if some one would be able to make one for me. In today's market that ain't going to happen, everyone is behind in production time.
He did say for my system the original designed for R12 condenser in the Monte is more than adequate for the R12 system. It's when you go to 134 it's the problem.
So decided to just do as i did before and clean the internals of that condenser which is easy to do, reuse it. Parallels are very hard to clean out the debris after a compressor failure.

Next is pull the system apart inspecting and a thoroughly cleaning the inners. Order a compressor, orifice and accumulator. After new parts installed on a clean system will need to borrow a scale and vac pump to get it up and running again. have done a few system to that extent now, hoping this is the last one i will do. The performance of this stock system with the correct charge of R12 has been VERY good for the past 13 years. Expecting to have cold feet and ice cubes out the dash vents when done this time. Just wasn't a project I needed to be doing right now.
Bob

#1071311 - 07/10/21 02:44 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Yes sir, after Lance's show 'n tell about his new condenser I looked into it. Found these and contacted them. 4 plus weeks out: https://www.originalair.com/1978-1984-chevrolet-el-camino-ac-condenser-parallel-flow

Same situation for the 3rd gen F-body condenser which is the application I'll be using for a serpentine belt swap coming soon. Like you, I decided to stick with a stock style condenser even though I'm sure in the heat of the summer sitting in traffic I'll wonder what might have been.


88 SS Black/Oxblood. Power Tour car
80 Malibu 2dr. Drag Week car
#1071313 - 07/10/21 05:44 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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Thanks for that A/C vender, will save it for next car A/C project.

Unfortunately that is what we find in today marketplace, stuff that was easy to purchase is not in stock and can't say when it will be available again. Besides working for a living for 50 years, done now, I've done appliance repair for the past 30 years as a sideline gig. Still doing that for car money today and have the same problem, parts availability. One of my window A/Cs stopped working, it was one of the good old R22 unit. The run capacitor failed, the wife said go buy a new unit. It took me a week to source the correct cap for it but for $11.13 I finally found a substitute and it's running great after a thorough cleaning and new cap. Priceless maybe, but did save me a few hundred on buying a new throw away China unit.

If doing a R12 to 134 conversation look into the new VOV, variable orifice valve, to replace the stock valve. I installed one way back when i did the initial 134 conversion on the car in 2000. Can't say there was noticeably better performance from the system but some of the car manufactures were using them on new cars for a while. And most of the system conversion, 12 to 134, recommended them being installed in place of the stock OV.

When I call ACKits to order my new parts next week will have the VOV conversation with Tim.
Bob

#1071319 - 07/11/21 01:29 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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86ttop Offline
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Murphy's Law, that's why now.!!


Leo Paugh
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POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs
#1071323 - 07/11/21 08:48 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Did they mention if you'd have to modify the manifold at the back of the compressor? I recently had to do that to my '89 Iroc Z, which uses the same R4 compressor as our Montes. I was able to find what I needed (AC Delco) on Rock Auto and kept R12 as the refrigerant...works great. I kept the original Harrison compressor in hopes that someone doing quality work can restore it.

Last edited by jmireles; 07/11/21 08:52 PM.

-'87 Monte SS LS 2/4L65e Quick Perf. 9" w/disk brakes
-'89 Iroc Z28 Stock 5.7 Edelb. TES headers, Borla Exhaust90K
-'77 Trans Am 468(Stroked) Doug's Headers Flowmaster catback
B & M shift Kit 400 Turbo trans. Edel brock Performer
RPM Intake Sean Murphy built Rochester Carb. Restored
in '08. 3K
#1071327 - 07/12/21 01:05 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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86ttop Offline
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Bob, have you thought about the aftermarket bolt in compressor? I guess you mean to stay stock appearing!


Leo Paugh
It's not an attitude, it's just the way I am.
POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs
#1071334 - 07/12/21 07:08 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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Leo, aftermarket bolt in not really an option. The stock R4 brackets were all modified, moved the compressor outboard 1 1/4" to allow room to pull taller than stock valve covers without compressor removal and also to tie the compressor mounts back to the #1 header flange location. Installing another R4 is the easiest and cleanest install.

Evaced the R12 yesterday, pulled the compressor, OV, accumulator to inspect the system. Also did an initial pressure flush of the system with naphtha to check for junk in the condenser and evaporator. The mineral oil removed was clean, just slight amber in color after 13 years of use. The OV I was thinking my have been clogged. But other than maybe 3 small specks of steel slivers and three very small black specks it was clean. Drained the compressor of mineral oil, same, amber and no dirt. Drained the accumulator, same no dirt and 4 oz of clean amber oil. So absolutely no signs of anything contaminating the system. the system was clean as a whistle when I did the R12 13 years ago and would say it's still that clean now.

On the phone to ACKits this morning, the compressor he found for me last thurs is now gone, he's looking for another new one for me. Besides no one has a condenser available compressors are hard to find no too.

Checked at several places to rent a vac pump, that is difficult also. Autozone said 200 bucks, Pep Boys has one but availability is the problem. My local car repair shop only has a Snapon big unit and is only set up for 134. Got lucky, an appliance repair guy I know lent me his pump and scale. A/C vac pump range in price from cheap, 70 bucks to hundreds of dollars. I was going to buy a 100 dollar pump but still needed to find a scale to use. So recharging now is a no brainer with borrowed tools.

Will have a qt of A/C flush sent along with the new parts and do a 100% cleaning of the system again before new parts go in. Already have the connections to the system in place to do that.

With a little luck, parts arrival, should have cold air blowing out the vents this coming weekend.

Always one to know what failed i will pull the old compressor apart tonight and look at the valves. It's the only thing i can think of that has failed.
When you do a search on info about an R4 compressor there is nothing, no info, out there that gets into the internals of the R4. Zero info on the guts. Clutch, front seal, front bearing, case seals info all over the place, ZERO info on the pistons and reed valves. Even a parts breakdown or rebuild procedure, NOTHING.
No interested in doing a rebuild, or buying a rebuilt, just a need to know what failed in my case.
Bob

#1071335 - 07/13/21 01:48 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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I hate when I can't find something wrong. I can't sleep at night because ill be thinking what else it could be.

After this thread and doing research I'm thinking I need a parallel flow condensor to help the cooling some. Talked to a guy at original air and he felt the ac system with the 134 and correct condensor would cool every bit as good as the original r12 system. It might be a little ways down the road but maybe a route I need to go. Probably be next summer but the planning can start.

Right now I just need to get the trans swapped.

#1071336 - 07/13/21 05:33 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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You're very close to having all the parts for that swap. A driveshaft the correct length is about it.

Just PayPal'ed a transaction to Tim, ACKits, compressor, accumulator, OV, and a qt of flush, hoping Fri delivery. He was pressed for time this morning but by 5pm here in Pa he had a compressor for me. Again finding a quality, new, not rebuilt that is on the shelf somewhere is not easy right now. Supposedly a new Delco was sitting on a shelf somewhere in Pa this morning. Not sure if that's the one i got. But, I do know a new R4 with be here soon. Right now just get me a good part.

Still looking for the reason for the crash of the system. With compressor on the bench spun the crank to listen for popping and a thumb over the suction side port to check for suction. Wasn't happy with those results.
Disassembled the compressor tonight, got the crank out of the case. The internals, crank, cool rod assemble, pistons, reeds, all laying on the bench.
NOTHING remarkable found!!!.
The clutch removal was simple, even had the correct tool to remove the plate. The clutch could be reused it's that nice, not overheated, lots of life on the clutch, bearing is surprisingly good and it was quiet.
Front crank seal and bearing very good. It is normal to have a little oil pass by that seal, their was just a little film around the area.
Had to cut the outer shell off the "block". Tried numerous crude ways of pressing, taping, driving, it off to no avail, ran out of patience, and the unit will be junk anyhow. Now you can see how simple the guts are, but how clever the crank/rods/pistons in this "Scotch Yoke" setup work.

First, no junk found anywhere in the crankcase or high pressure side (under the outer cover),clean everywhere.
Now spinning the crank watched the exhaust reeds, hmm would expect more exhaust than that.
Pulled the exhaust reeds, HD internal snap ring and they pop out. Top of the piston exposed now. Intake reed is on top of the piston, nothing abnormal anywhere, clean.
The alum pistons centerline are threaded to the alum connecting rod via a steel stud at each piston. To remove there are 6 small holes in the top of the piston to use a spanner of sorts to loosen the piston from the stud. A center punch worked well to break them loose, yep pistons are junk now, but out of the bores.
Once the pistons are out the crank can be manipulated out of the block. I've sure in production that happens a lot quicker.
All four cylinder bores are very good, pistons look good.

For a piston sealing ring it is black, 3/16" wide and probably Nitrile used in an R12 compressor. Also the large outer shell is also sealed with black O-rings. A R134 system/compressor internals today would be green, HNBR, o-rings and pistons seals I would think.
This compressor was spec'ed as an R12 when i bought it 20 years ago, thus all black, Nitrile, seals.

At this point in time can't put my finger on why for some reason this compressor stops doing it's job, It's a simple rotary, 1,2,3,4, and do it again.Visually everything is exceptional on it for 20 years of service. The only logical conclusion is the piston seals gave up, no suction and nothing to compress. A little more inspection of those seals later. But that's the hunch.

Onward and upward,
Bob

#1071337 - 07/13/21 02:06 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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What were the pressures you saw when you hooked up to it when working? And what was the outside temperature?


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071338 - 07/13/21 03:41 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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SSLance Offline
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Any chance it was a blend door issue that was just not pulling circulated air across the evaporator?


Lance
1985 Monte Carlo SS Street Car
#1071339 - 07/14/21 02:07 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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I hear you Bob, didn't know about the change in the brackets, good luck with the parts you've ordered!!


Leo Paugh
It's not an attitude, it's just the way I am.
POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs
#1071363 - 07/19/21 03:13 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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Has been over a week now with the A/C down in the car. After some effort to get replacement parts a compressor, accumulator, orifice valve and a qt of flush is scheduled for delivery tomorrow. I gave up on trying to find a parallel flow condenser that would be a bolt in for the old tube and fin. It seems that is just another part that will be hard to obtain due to the pandemic. Replacing the condenser is not a necessity because the system will be R12 but would have been a nice upgrade to make it more efficient.

Checked blend door, blower output, and related under dash parts, everything is working properly.
Pulled the orifice and dissected it, perfect like new with but a couple specks of black, maybe O-ring and a couple specks of silver (alum), probably from the compressor's initial manufacturing. So orifice tube causing the problems. absolutely not.

Flushed the condenser, flushed the evap, nothing but used mineral that is now amber instead of clear in them. Both places are collection points for debris in the system but no dirt in the flushed fluid worth noting.

Pulled the accumulator and drained the oil, same results, amber but clean.
Drained the compressor and got 4 oz of amber mineral oil, zero dirt.
Disassemble the compressor down to pulling the pistons and crank, the inners of this compressor are near spotless.Bearings and journals outstanding. Cylinder walls look good, pistons good, valves appear good, only questionable was the seals on the pistons. Has something made them not seal as well? Cranking this 4 cylinder rotary 2 cycle over you should hear all four exhaust reeds pop, 12341234, that was not obvious. Is it bad reeds valves (intake or exhaust), seals on the pistons, none of which are possible to buy.
Compressor is laying on the bench awaiting the recycle bin, old accumulator will be keeping it company. Old clutch is very nice and will go on a shelf somewhere with other parts I hope i never need.

In trying to understand the the odd gauge reading I got at the start of this system failure, high center vent temps, high low pressure, low high pressure, the culprit is usually orifice or a pressure control valve related, but could be weak compressor or inefficient condenser. None of the above seemed to be the culprit.

Finally stumbled upon the possible real problem. When the dual Spal fans are running they are noticeably loud on high speed. After awhile they are just part of the music with the hood up. The AutoCoolGuy PWM fan controller installed three years ago had been flawless, seamless in running the fans. When cooling the engine there is a primary and a sec fan. When the coolant temp sensor calls for fans the pri turns on and if necessary speed increased to effect reduced coolant temp. The sec fan will turn on at full speed if the pri can't get the job done.
At rotary switch is used to select the fan turn on temp. Works great, never overheated. Never had to think about the fans operation, until now.

When the A/C is turned on I've wired the system so a high pressure switch "requests" the controller both fans full high speed. When operating correctly the cycling low pressure switch activates the compressor clutch, the high pressure in the system increase and the high pressure switch turns on the fans. The fans cycle to maintain normal high pressure for a R12 system. Most new cars do it this way, they just use a smart PCM to run the fans.
Couple advantages of high pressure fan cycling. The fans aren't running the entire time the A/C is on. Using a low pressure switch to turn the fans on will cause the fans and compressor clutch to hit the electrical system at the same time and adding to that compressor rotating load the engine sees, rpm drops at idle.
One other advantage to high pressure cycling is when mph is fast enough possibly enough air flow through the condenser without fans running. If using low pressure switching the fans would be on and off frequently as the clutch was activated.
Another advantage is when it cold outside and you need to defrost the windshield both the heat and A/C are used. High pressure side would be very low. Not running the fans unnecessarily would allow faster engine warm up. Why pull cold air across the radiator when you want to heat it and why blow cold air on an engine you are trying to heat up.

Another feature of the controller is fan override, a switch on the console will turn both fans on high. I've used that at the drag strip on hot days running passes round robin.

Time to cut to the chase. Taking for granted both fans were operating correctly was a big mistake. At the start of this diagnosis when the A/C was turned on i heard the fans, or so i thought. It was only the sec fan that was running. Never for one moment though it was only one fan on. A friend at that time even put a piece of paper to the grille as a joke and it stuck to the opening. It was days later after the system was apart that I was checking blend doors and motors that i saw only one fan was running when the overide switch was on. DAMNIT.

Reversed the plugs on the fans and confirmed fan motors are good. That's a plus because Spal will not sell you a new motor because" fan and motor are a balanced assemble". A new Spal dual 11" is now 400 bucks, almost twice what i paid years ago. So fans are good, yea! Oh, by the way Spal is another company gobbled up by Holley. When I did the initial Spal fans and a Spal controller 15 yeas ago I had numerous phone conversations with the Spal engineer that designed the Spal controller to get the correct thermister value (temp sensor) and interface the A/C request circuit correctly. Now that Spal is Holley I'd bet that can't happen anymore.

Next is pull the controller, remove the case cover and inspect, looks like new, no visual corrosion or overheating. That night at 1 am send the Autocoolguy an email in CA. Got a reply at 9 am here in the East the next morning, talked on the phone at 1 pm, my controller was on it way to CA via Priority mail before 3 pm. If I'm lucky it may be back in my hands by the end of the coming week. Darryl is a standup guy and i believe in his product, he says 24 hour turn around once he gets it. My guess is one of the big MOSFET took a dump.

So looking to put this behind me by next weekend. I'll admit it was my lack of attention to the fans that is probable he reason I tore a perfectly good system apart.
I just took something for granted without looking, I heard a fan or fans so i thought.
The Spal dual 11" are not huge cfm ratings, 2720, so one fan is 1/2 that, 1350. I've tried to find a piece of info on just that scenario, reduced air flow and effects on vapor condensation, vapor going to evap, anything that explains the odd system pressures but find no help. But believe 1350 on a 90 degree day sitting still doesn't cut it.

About one month ago made 14 autox runs on a 90+ day, the engine got very hot, had to pull the plug on the final 2 more runs we could have made. On the 80 mile trip back home the engine temp was just slightly elevated but remained steady. About 70 miles of the that trip were 55 and higher mph. Being tired from the long day, trying to get a car home that had a overheating problem but did notice the A/C was good. Two weeks later another 100 mile trip home in the late afternoon from Chevy Nationals, high 80s, again most at 55+ and did notice the A/C didn't seem to be up to par.
It wasn't until another mid 90s day a week later that around town center vent temps were way to warm.
All those events may be caused by just one fan operating instead of two.
Just not sure how I could have missed something as simple as that, but i did.

Did i mention when you are on Medicare periodically you get what is called a Medicare Wellness Check. A bunch of simple questions, steps, railing, throw rugs, grab bars the usual old people hurdles to navigation. But one aspect of the test is, "here are three words to remember, later I will ask you to repeat them". Well from my years of schooling i know 2 out of 3 is 66%, is a failure. Guessing my lack of remembering to cover all the bases on the A/C problem may be related to the Golden years.
Oh, next time for a wellness check will have a pen in my pants pocket, write the three words on the palm of my hand, also something you learned in school.
Bob



Last edited by mmc427ss; 07/19/21 05:26 AM.
#1071366 - 07/19/21 03:15 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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SSLance Offline
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Dude!!! Well the good news is at least the system is all nut and bolted and ready for the next adventure (or will be soon anyway).


Lance
1985 Monte Carlo SS Street Car
#1071367 - 07/19/21 03:47 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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If it helps, high low pressure and low high pressure would normally be weak compressor and/or an orifice that is too open (blew apart, or leaking past the sides?).
Low condenser airflow should give you high high pressure instead of low high pressure. Mild ambient conditions would still give you cold (enough) vent temps, it would just get warmer under hot outdoor conditions but the low side pressure should be fairly normal. low condenser airflow basically makes your AC on an 80° day act like it's 90° outside, 90 acts like 100, etc.

Leaking orifice valve would give low high pressure and high low pressure, vent temps would be not as cold but should still feel cool.
Weak compressor would give low high pressure, high low pressure, and warm dash temps, depending on how weak the pressure differential would be.
Low charge would be low on both pressures. Blockage give high high pressure and low low pressure.

Your fan not working is definitely something that needs fixing, but I think you still had some kind of compressor issue. Might have missed it, but you did confirm the clutch was working correctly, fully engaging?


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071369 - 07/19/21 04:40 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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Thanks Shawn.

Kinda what I suspected with the readings I got. The orifice looked like new and didn't appear to be bypassing it or restrictive.
The compressor clutch was working very well. The first thing I noticed on diagnostics was the compressor belt was slapping at idle which it never did before. My first thought there was an internal comp problem. Disassemble of the comp showed nothing internal that would cause the belt slapping. The exhaust reed valves didn't appear to be stuck which may have contributed to the compressor problems, compression.

I never noticed the compressor running hot.

Being mineral oil hasn't been used for near three decades now I'm curious about the amber color of the mineral oil i removed. Not sure if it's the aging process of mineral or is it an indication or overheating the mineral oil. The virgin GM mineral oil I have is clear.
Bob

#1071391 - 07/21/21 06:00 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Parts arrived on Mon, shot a coat of black on the bare alum front and back sides of the compressor last night.
The new compressor is a Delco, box says Made in the USA. Hoping that's a good thing.

Was thinking about pulling the condenser to clean the bugs off the front face but after inspection it is actually good. Make a long pick to stick through the grille opening and get rid of a dozen bug eyes stuck to it. Have several long brushes and could brush and blow off with compressed air the remainder of bug debris. Condenser face is as good as it can get.
Started the condenser and evaporator flushing process. With two qts of A/C flush on hand condenser and evaporator were flushed in both direction three or more times. Initial fluid flushed was clean of debris, zero, and came out a little amber colored. Used the second qt as the rinse in both and totally happy with the cleaning. These fluid have a very high evaporation rate. Blowing high pressure air though them should get rid of any of that fluid left in them. I know the condenser being just a tube and fin design it will dry 100% when done.

The evap being a cross flow is much more difficult to flush. Rubber hoses were attached to the inlet and outlet and evap filled 100% with flush, let sit for 15 minutes and use low pressure air to blow the fluid into a collection bottle. This process was done several times, inlet then outlet applying air pressure. The problem I see is evap design doesn't allow the bottom of the evap to be purged of all fluid due to the cross flow design. Ideally removing the evap and turning it upside down with air pressure to purge it completely would get the job done. But that isn't going to happen. Tomorrow will again go through the purging via high air pressure process to hopefully get rid of all the flush from the evap. From A/C forums I've read contamination from flush that wasn't totally removed can be a problem. And when the system is sucked down via vacuum that isn't a guarantee all the flush has been evaluated. So will again do multiple blow through of the evap and hope to get all the flush out.

Tracking says the fan controller was deliver on Mon. Emailed him to confirm he has it in his possession, will look for a reply tomorrow. Was hoping it would be back in my hands by the end of the week but not seeing me driving the car this weekend.

Once happy with all the flush out of the system will reassemble and draw down a vacuum and leave it overnight to see if it holds. Not going to use nitrogen, just don't have a simple source for that. Had zero leaks the last time I R&Red this system because of paying attention to all the details. Even more anal now than 14 years ago, should have equal or better results results this time. I do need to find a replacement for the high pressure schrader valve. Factory valve is a little odd looking, have several new A/C schrader valves but slightly different color and size seal on it. Minor detail but a detail.
Bob

#1071417 - 07/23/21 06:43 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Time marches on, car ain't been driven in two weeks.

No controller yet, talked to Autocool Thurs afternoon, nothing on it's way back to me yet.

Hindsight, should have just left the evap alone instead of triple flushing with A/C flush and air pressure. You put near a qt in and get back 2/3 to 3/4 of it. The rest lays in the bottom of the evap and takes a long time to evaporate down there in the bottom of the pit.
Evap rates on A/C cleaners I used are very fast. An air line is attached and air blown into the evap inlet, then switched to blow into the outlet, regulated air from 10 to 80 psi. Over the last couple days did a hundred cycle of that to get rid of anything fluid in there.
I've read that you need a very high cfm blown into evap to be effective for drying the evaporator in a short period of time. The shop air just can't blow near that much, so the slow and steady approach was used.

The alternative to that debacle is removing the evap from the suitcase so you can just dump the flush out of it. MUCH easier way to clean an old evap. You could always just install a new evap instead of cleaning it, and while in there throw a new heater core at it. Anyone who has opened that suitcase knows it isn't a fun time. Been there, done that 20 years ago when the heater core was replaced and evap outsides cleaned and also the drains inside the suitcase.

When I opened the A/C system and saw the orifice screens were clean, the compressor internals spotless, the condenser fluid flushed was clean, no signs of debris in the mineral oil anywhere. Thirteen years ago the evap was flushed with mineral spirits through many cycles and then flushed again with lacquer thinner several times, both direction on pressure. Evap and system worked great on R12 until a month ago. Evap didn't need cleaning this time around.
Hindsight, think before you leap.

The Made in USA compressor thru me a curve ball. Once the paint was dry next was bolt on comp mounts, done. So next is fill the compressor with mineral oil. I pull the shipping plug plate, it covers the suction and discharge ports, and turn those ports facing down and expect no oil to come out the holes. SURPRISE. Quickly got a bowl and drained the fluid into the bowl. Caught most of it but figure 6+ oz was in the compressor.
The reason for the surprise was the orange sealing tape on the shipping box said Must Add Oil. Scotch taped to the outside of the compressor shell is an orange instruction sheet. It's covers boldly states, SERVICE COMPRESSOR. MUST ADD OIL. Opening the instruction sheet at the very top of both pages it states in large letters, MUST ADD OIL. So surprise, it's overfull with oil. And to top it off what kind of oil is in there. Is it mineral oil or is it PAG. PAG is a no-no with R12.
I did learn that there is a color coding of the instruction sheets that is scotch taped to the shell. ORANGE is NO oil, PINK is 3 oz, YELLOW is shipping oil and GREEN is 134 or 1234 oils. Four Seasons, a major car A/C parts supplier, has a good video on compressor installation. But just adds a little more to the confusion of why there was oil in my compressor.

So knowing you don't use A/C flush in a compressor Mineral Spirits went into the crankcase and flushed twice and drained. Into the discharge port 4 oz of mineral spirits, this rinsed only the exhaust side of the compressor. Was able to dump out 98% of the mineral oil out of the compressor. During all of this the compressor internals were not rotated to try and prevent the piston seals from getting washed. The seals on the pistons and the front compressor seal are my concern with flushing the unit. Also the compressor is always handled with the clutch facing up to keep any flushing/washing of the front seal area. And also need to add after the new mineral oil goes in the compressor needs to positioned clutch down for 10 minutes so oil runs into the front bearing and seal area. Those front seals are notorious leakers.

The compressor has sat near two days with the ports the low spots. Next is pour a measures 6 oz in the suction, crankcase, and insure everything get a flushing with clean mineral. Then drain and measure exactly what I get out, hoping almost all of it. Then a fresh 3 oz will go back in and then rotate the crank and get mineral all over the cylinders and all those pretty needle bearing in there. This is the same method I used on the old compressor when it was changed from 134 back to R12 years ago.

On the discharge side 1 oz of mineral will be added, compressor rotated several times to spread the mineral around the inside perimeter of the compressor shell. Then turn the discharge port down and measure what comes out. What ever remains in the discharge side should be pushed down the discharge line to the condenser in short order. When putting oil in a clean system you spread the 7 oz of mineral in every component, the condenser should get 1 oz. Any oil on the discharge side of the compressor will end up in the condenser quickly.
Another 1 oz goes into the evap inlet and the last 2 oz go into the accumulator inlet.

Before the compressor goes on the car the compressor sits 10 min face down.
Once installed on the engine, the system buttoned up the compressor gets spun at speed for a few seconds to insure it's rotating freely.

Another step in the whole A/C refresh is burnishing the new compressor clutch. They say engage and disengage 10 times to clean and heat the clutch faces and then let if cool before putting it to work again. Brakes, clutches, now gotta bed the A/C clutch, ok.

Today the a nice evac vac pump and a digital scale to weigh in a charge showed up. Got a few hours tomorrow and Sat so should have the system ready to weigh in 3.25 lb of that good old R12. But can't do that until the electric fans are literally up to speed again.
Will evac the system for an hour then let if sit for an hour. Suck it down for another 1/2 hour and let if sit overnight to see if it hold the vacuum. Fingers crossed.

Got pretty tired of relearning all this A/C stuff. This is only my fourth time for doing a complete system servicing, third on this car and once on my 95 Astro van.

Aug 7 is another autox event i want to run the car at, two weeks away, need to have the car back together and reliable to do that event. A check of registration says there are still plenty of opening left on that day, but it will fill up fast in the next week, gotta be done with this project soon.
Bob

#1071427 - 07/24/21 12:54 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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#1071435 - 07/25/21 05:39 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Couple updates.

After finding the 7 oz of fluid in the compressor drained it, flushed with mineral spirits , drained overnight, added 4 oz of mineral and splashed it around the internals, drained and got 3 oz back out, added 2 fresh oz into the suction (crankcase), put 1/2 oz into the discharge port then put the shipping plugs back on the compressor, rotated the crank to get mineral everywhere inside, let sitting clutch up to get oil into the rear needle bearing, and clutch down to get oil in the front bearing/seal more than 15 minute for each. Compressor ready to install.

Needing to know why a compressor with orange Must Add Oil warnings all over it, had 7 oz of oil in it, so I called ACkits where i bought it, Tim on Fri. What i was told was never take for granted anything about oil in a new compressor, always drain whatever is in there and add whichever fluid type and quantity is appropriate for your Freon. So don't assume nothing is correct. He did mention some of the new PAG oils are compatible with mineral and compressor makers will put that in replacement compressors. So most likely it was PAG in the shipped compressor.

For a total of 7 oz of mineral in the system, 3 in the comp, 1/2 in the discharge side of the comp, 1/2 in the condenser, 1 in the evap and the remaining 2 went in the accumulator. New orifice and accumulator, green O-rings, mount the compressor back on the engine, seal up the system, ready for evacuation.

New P/S and A/C belts are part of this R&R, picked up Gates at my NAPA. Old belts were Gates, same part number were bought. When the engine was still on the engine stand the stock A/C brackets were heavily modified to move compressor 1 1/4" outboard. Taller than stock fabricated valve covers, heads with raised exhaust ports, and the need to not pull the compressor to remove the valve covers necessitated bracket changes. A 1" longer than stock A/C belt was needed for correct belt length, a 7570 belt.
Today's problem was when i went to put the new 7570 belt on it was to short, how can that be, old 7570 was the perfect length. Even with the compressor at the beginning of the adj slots belt was to short. Nothing has changed on the compressor mounting hole locations. The clutch pulley from the old and new are identical. Puzzled!
A trip to Napa and got a 1" longer belt, now to long. Another trip and exchanged for only a 1/2" longer, a 7575 will go on tomorrow, I hope.

Why the belt problem? After looking at specs for the 7570 belt on Gate's web catalog, specs advertised on Rockauto for the 7570 and the specs on the sleeve that comes with the belt you find they are all over the place. The one thing that stands out though is the pitch on the Vee of the belt. Gates says it's a 37 degree and Rock says it's a 36 degree. Not that I believe Rock's info. But in the past it may be possible that Gates was 36 and went to a 37 recently. A 37 will sit higher in the pulley groove, effectively shortening the belt. Do I think that happened, it's the only explanation i can find for a new 7570 not replacing an old 7570.

Called about my electric fan controller which is still out in CA. As of Fri afternoon zero good news yet. Getting a little worried at this point about a happy ending.
By Tues I will need to move forward with an alternative method to cool the condenser and rad. I still have my original clutch fan and shroud up on the mezz. That would be the simple choice, a dozen bolts and it's switched back to a clutch fan.
There was a reason I choose the Autocoolguy controller i bought three years ago, size, features and it appeared to be the only reliable controller on the market.
Still hoping I was right. installing any other controller would require tons of work to hide it somewhere and do all the wiring over to feed it.
Bob

#1071436 - 07/26/21 12:10 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Having nothing but time on a gorgeous Sun afternoon I'm brooding over the same problem I had three years ago. Finding a fan controller that does what I need it to do RELIABLY.

The SPAL PWM that proceeded the AutoCool was in the car for 10 years. Spal had problems early on with reliablility of their unit. The unit I had was a very early production controller, bought it from a local company that sells car wiring solutions and such. Spal sent it to them as a trial unit. At that time, 2006, there wasn't really any choice in a PWM controller, pretty much stuck a thermometer in the rad core and open and close some relays to run the fans.
That Spal controller was among the first to control two fans of moderately low amperage, 25 per fan. And particularly SPAL fans, not the monster CFM lots of guys were stealing out of factory cars.
On engine cooling a thermister in the thermostat housing would turn on the primary fan at low speed, increase speed of that fan trying to satisfy the thermostat housing exit temp. If the pri fan ramped up to full speed and engine temp not satisfied the secondary fan would come on full speed and the two fans would get the job done.
The Spal had A/C request and also an overide feature to run the fans anytime you need both full fan speed.
The demise of my Spal was moisture got onto the pc board at the touch pad to adjust the high and low speeds. An autopsy of that unit confirmed that, corroded board.
From what I've read of others running that Spal PWM was it didn't last very long, just a few years or so. From talking to the designer of the Spal he said my controller was one of the very early runs, made in USA. Spal corporate made the decision to move production "over seas", reliability became the problem.

Fast forward to 2018, Spal conroller dies. After a long search for a replacement the AutoCool 85 was bought. At that time the Derale controller was having serious reliability problems. DCC controler could handle high current but was basically just a brute fan controller, no A/C request and not PWM. The rest of the controller market were just rad sensors turning on external relays. Dakota Digital didn't have anything to offer in a stand alone unit at that time. The Autocool unit was the smart choice, small enough to hide, PWM with soft start motor tech, was capaable of 85 amps, A/C and overide request, runs 1 minute after engine shutdown to cool rad, cycled only the primary fan on engine cooling until the sec was needed at full speed, weatherproof, no digital programming required just set temp on a rotary switch, and it got it temp input from the lower radiator hose sensor location. It was perfect, did everything it was supposed to, seamless and set it and forget it.

Now it's maybe that I'm back in that same search mode looking for a controller that does everything required, lasts more than a few years, and doesn't require a degree in programming to set up.
The new Derale 16796 has many features, is limited to 65 amps draw, has soft start now, runs both fans simultaneously (no pri/sec fans, they behave as one) and now the coolant temp sensor is located in the exit of the radiator. The unit is small which kinda scares me. Heat is the enemy of solid state, can it get rid of the internal heat through a small size and small heat sinks. Unfortunately the internet being what it is today all you get is buy it here when you look for any input on it's reliability. Very little feedback on it, and most is 5 or 6 years old. So it would be very hard to sell me a Derale controller.

The Dakota Digital control I think is fairly recent. I was never a Dakota instrument cluster fan because of in it's infancy Dakota had lots of problems with clusters. today that may not be the issue, don't know that. They now offer an entire line of high tech interfaces.
https://www.dakotadigital.com/index.cfm/page/ptype=results/category_id=646/mode=cat/cat646.htm
A fan controller is also available.
https://www.dakotadigital.com/index...207/category_id=-1/mode=prod/prd1207.htm

To many things i don't like about it. Must be installed in the cabin as in not weatherproof. Uses relays. To many steps needed to program it. And is it truely a standalone controller. Price is reasonable though.

So back between that rock and a hard place once more.

Would love to hear from Autocool, PWM 85 is good to go again.
Have done numerous repairs to pc boards over the years, it comes with the fact almost all appliances, devices, we have these days are processor driven, pc boards in everything.
I had the Autocool cover off the unit before shipping it out. Two principle components stands out, the 4 large MOSFET and a fuse on the board for each. My guess is one or the other on the pri fan side of the control has died. Repairing/ replacing any is a PITA. For one reason the two pc board in the unit are are sandwiched, the other is the boards are sprayed with weatherproof sealer to prevent corrosion. A simple replacement of the MOSFET or fuses requires surgery. I have the tools needed, just not the patience these days to get the tedious job done.

Hoping for a some satisfaction from Autocool but need to have a alternative plan in effect. Just clueless what that is right now.
Bob

#1071438 - 07/26/21 01:19 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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You know what I use for a fan controller? Holley EFI... Works perfectly and is 100% adjustable. laugh

Hope you figure it out soon, August is coming up quickly...


Lance
1985 Monte Carlo SS Street Car
#1071439 - 07/26/21 01:30 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Yes I know your EFI takes care of that.
Yes I know Aug is soon upon us. The Aug 7 autox I wanted to run is almost here, no engine cooling, no A/C puts that in jeopardy. But one way or another the trip to KOTM will happen. Still have one month to get the car together.
Bob

#1071440 - 07/26/21 01:38 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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I know it's hack-y, but a couple of switches and HD relays would let you turn one fan on constant for driving around, then add a second if the AC performance isn't quite what you are looking for, or kick them both on for a run to make sure the engine stays as cool as possible. Not the best for long life and easy operation etc, but to be able to make a run at an AutoX and won't hurt much for a couple weeks until you get a solid solution in place.

My other thought is that they make PWM 12V relays, if you like a controller but don't trust the current rating. Use the outputs to drive a solid state relay that is rated for plenty more than you need but would be more reliable than pushing the limits of the controller itself. Finding one with high enough amp rating and sealed for underhood conditions might be a challenge, but if you don't want to run wires inside you may be able to fab a small enclosure to take care of the water spray issue.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071443 - 07/27/21 01:19 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob, I wish you would get everything straightened out so your ac would help cool it a little down here in the south, its been brutal.

Did you ever come up with a size difference between your controller and mine? Any word from Daryll today ontestimg your controller?

#1071448 - 07/27/21 06:14 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Yep, the PWM 85 is 4 3/8" wide, so a PWM 125 at 5", won't fit inside the raincoat box nestled behind the battery.

Going to make this short,
Unexpectedly the controller was dropped at my front door by the mailman, or do i need to say mailperson.
Puled the cover off at the kitchen table to see it anything looked different. It appears the four MOSFET, big transistors mounted on the heat sinks, where changed.
OK.

Tonight reinstalled the 85, battery back in the car, turn on the override (failsafe), zero, zippo, nada, nothing. Installed a jumper across the A/C high pressure switch plug which should turn on the fans, zero, zippo, nada, nothing.

Pulled the three fuses, all good.
Disconnected the battery and went home, pissed.

Will meter everything tomorrow to make sure the BAT, IGN, GROUND, 12+ to the fans are all good, but I already know that but will check again.

Not sure what my next conversation will be with Darryl. I do know I entertained the thought of an 8 lb sledge and the 85 meeting eye to eye.
Bob

#1071452 - 07/28/21 01:52 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Were you able to find anything today? I've thought all day how mad I would be if the controller still didn't work. Its one thing if its not fixable but to send it back with no type of communication.

#1071453 - 07/28/21 05:59 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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This afternoon after my post op checkup at the doctor's, yep BP was up, had time to play with the problem child. Manage to manipulate the controller it into a horizontal position with all wire connection facing up so i could meter the 7 inputs. BAT, IGN, A/C request, ground resistance, battery voltage all good. When I would request fan via the high pressure switch or the fail safe a funny thing happened the sec fan turned on at a very slow speed, that was it. HUH! It wouldn't do that in previous attempts, had no fan response. The controller's chassis was attached to the radiator support grounding it, it is now unattached and sitting free air. When a wire was then run from the controller to a car chassis ground that fan shutoff, remove that ground the fan went to low rpm again. HUH!
I
So now there's a little more info collected and time to call CA, 4 pm there. I knew I was going to have trouble minding my manors. My conversation started from scratch again from the beginning to refresh his memory. He said he tested it and it was good to go. When i mentioned the odd ground he said a bad sensor will cause problems with the programming if one sensor lead is grounded. Check the sensor's ohms again, 43.5K, that is right on spec. Disconnect the sensor from the controller and jump the two terminals, both fans should go to full speed. Call him back let him know what I found.

Tonight went back to the shop and ran the tests, Sensor is fine, not shorted, not damaged, ohms good, everything good. Jumped the two sensor terminals and the sec fan came up to full speed. A ground jumper installed between a car ground and controller chassis and the fan shut off. remove jumper and the sec fan runs full speed. Just to rule out a bad fan motor reversed the fan leads again the other fan ran at full speed and sounded good.

It's obvious to me the grounding, ungroundind of the controller chassis has a lot to do with the problem. Somewhere a path in the logic got shorted. You can kinda split the controller into two halves. The primary fan side that is PWM and answers to the coolant temp sensor and also commands the sec fan to come on full speed when it needs help. When in A/C or fail safe both fans are switched to high speed. If the sec fan was able to run full speed when I jumped the sensor and the pri fan did nothing it sounds like the brains of the operation went to lunch.

Will pull the controller, put it in the same box he sent to me on Mon and post office it tomorrow at the end of the day. Will call him after that and tell him it's back at his door step Sat. I'm trying to be patient.

While doing this whole impatience thing have been looking for anything available for controlling of two fans, PWM, A/C request, fail safe, 80 A, not a stupid stick a thermometer in the rad core sensor, soft start tech, not to big, weatherproof, maybe even fan timed run on after shutoff. There simply isn't anything comparable to the AutoCool controllers for this versatility. And cost wasn't a consideration, just wanted a controller that did everything well.

I've looked at the DDC controllers, lots of good comments about it but delivery times can be long. It now uses a stick on sensor to be stuck near the rad outlet area to monitor return coolant temp. Has soft start, and most features but finding any real info on how it performs is about zero.
The Autocool sensor is a MUCH better setup located in the lower rad hose. Using a pyrometer shot on the sensor's black copper coupler Tee you can see the temp of the coolant going back into the pump. A rotary switch is used to increase or decrease that set temp, which then controls cfm applied via fan speed to get the job done.

So as a plan of attack when i talk to CA tomorrow will probably have him send me a new 125 PWM. I've ruled out all other controllers, just like i did 3 years ago with this 85 becoming the choice. By Sat I maybe could have a 125 in hand to figure out how not to trash the nice harnesses. A 125 is wider that the old 85 and might require some rad support surgery for another 3/4" width. need to have it in hand to eye up the install. Could always just return it unused, just more postage. Sure would be nice if he had a new 85 sitting around to throw in car. But like most every business nobody has parts.

Tomorrow's another day, nearing a month and no car.
Bob

#1071457 - 07/29/21 05:12 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Ran through all the testing of the 85 again today. failed, only secondary fan would run, zero response on the primary. Pulled the unit, boxed, dropped at PO, back to CA again. Called Autocool, told him what I found and that it would arrive on his doorsteps again for a second look at it. Also told him I'm out of time playing with the 85. With the only logical choice to replace the 85 another Autocool was ordered tonight, an Auto Cool III 125 PWM, in black. May have it by Sat and can start fabbing a new raincoat/mount for it. The 125 is about 3/4" wider than the old 85. Reworking the wiring doesn't look like much of a problem fortunately.

Just like all sports my car's fun is still awaiting fans.
Bob

#1071458 - 07/29/21 01:24 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob, I just now noticed that you are ordering the Auto Cool III 125 pwm, the controller I have is the Auto Cool HF-125 pwm. Im sure both 125 controller's are the same size but I wanted to point out that difference. I went with the hf-125 so I could use it with either brushed or brushless fans to keep options open or atleast that was my thinking at the time and also no worry about the buzzing with certain fans.

Just for informational purposes for anyone that might run across this. The Hf controller will power one or more fans by bringing both fans up to the needed speed to maintain temperature coming from the sensor in the lower radiator hose. The Auto Cool III 125 will bring 1 fan up to the speed to maintain temperature and bring the 2nd fan up to speed when needed, so It independently controls each fan. Im not sure if one is better than the other as they both have a lot of the same options but there is difference. Bob has researched it more so im sure he can add too this.

I hope you get some resolve soon, your car being held hostage due to shipping and parts problems is a helpless feeling and it seems with every parts purchase its getting to be more of a hassle.

#1071459 - 07/29/21 06:33 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Until I have the Cool III 125 in hand won't know what the physical size difference is between it and the 85. Darryl says it's just a little wider.
Went with the Cool III because i liked the way the primary fan turned on first then ramp up speed and then the sec fan kicked in if pri fan wouldn't satisfy engine cooling. It just seems the current load satisfying just one fan to start would be less than starting both fan at once.
Even though the Spal dual 11" current draw is not that much previously with a 100A alternator it would dim the headlights for a split second. Now with a 140A alt it's not noticeable when the fans hit the electrical system.
Bob

#1071461 - 07/31/21 03:02 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Not much progress.
The A/C cleaner that spit out the hose during the evap flush, that got on the left fender, that took the wax off and down to dull lacquer got compounded, buffed and a coat of wax. Just another day in the year for a 35 year old black lacquer car. Some call it patina.

Hooked the vac pump and gauges up to the system and ran it for 1/2 hour to see how much and for how long it will hold vac. Tomorrow should be at the shop and will check it. You really never know how accurate a gauge is when you are talking about 1" of vac on a 30 scale. Gauge said 30 while sucking the system down, 28 1/2 when I pulled the plug and disconnected it from the manifold gauges set. In my neighborhood 29" would be a successful evac.

Once I get past this fan dilemma will do another evac of the system before charging it with 3.25 lb of 12.

Went through the scrap pile again and found another clean sheet of alum to make another controller mount. Would be nice if the new controller fit in the old mount but not my luck. Being there's some TIGing and painting to be done to a new one looks like a another week in the dumper. Autox next Sat is a no go, maybe be able to make our next in town car show.

Got a tracking number tonight, Mon morning delivery of the 125.
Bob

#1071465 - 08/02/21 01:19 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob, an Auto A/C instructor told me long ago that you never really get 30" of vacuum, even though the gauge reads 30". Good luck with the system and the fan controller. I think you should do something to save this blog for future reference!


Leo Paugh
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#1071470 - 08/03/21 06:06 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Leo you live a little closer to sea level than me, but as you said 30" is the perfect world.

Today was a good day. New Cool III 125 showed up at 3 pm. Quickly out of the box and measured the width. Hmmm, just a little wider than the 85, maybe an 1/8".
Later this evening was a trial fit to see if it would sit in the old mount/raincoat. WOW a little less room for air circ on the sides, heat sinks, but still enough. There are screw mounting holes in the corners of the controllers, they lined up exactly where my 85 was attached. So yippee, old mount and new 125 can be reinstalled without making a new box.

I did make a tweak to the box. One of the features of the AutoCool controllers is you can adjust the electric fan speed when A/C request is turned on. You pop off a 1/2" plastic hole plug and there is a pot inside the controller to adj A/C fan speed. You may not want the fans running at full speed to satisfy cooling the condenser.
That plug was not accessible when I installed the 85 controller 3 years ago.
Took care of that tonight. Drilled a hole in the box aligned with the hole in the controller. Then attached the mount back on the rad support, did some measuring and drill a hole vertically down through two layers of rad support to align with hole in the box and the hole in the controller. You start small and move the holes with a round file. A section of 1/8" fiberglass rod with a slot screw tip about 10" long and I'll be able to weak the A/C fan speed by just popping the plug on the controller.
A couple of touch ups with flat black paint and nobody will ever know those holes are in the rad support for a reason.

Because I run my A/C request to the controller, 12+, and my fail safe request, 12+ also to the A/C request is the primary reason to be able to adjust the speed of the fans. The 125 has a separate fail safe request but it is simple a switched ground circuit. To use that feature would mean reworking the wiring for the fail safe switch in the console all the way to the controller. Ain't going to happen. So being able to adjust the A/C fan speed will impact the fail safe speed. Now with being able to adjust that easily I can find a happy medium between A/C fan and fail safe speed. Most likely it will be near or at full speed.

Called the AutoCoolGuy, Darryl, at 9 pm my time, he answered the couple questions I had about wiring the controller. The 125 is a 125A controller, my Dual Spal 11" fans are 50A or less total. The 125 has two chassis ground posts, 10/32 studs, my 85 only had one. I ran a #8 to the old 85 which can handle 75A+. Going to make a solid brass jumper between the two 125 chassis posts and then tie my #8 to one of them. Those two chassis ground studs are connected at a common ground area on the 125 pc board. There is really no need for the brass jumper between studs, overkill, but just the way I do things.

Have sucked down the A/C system three times now watching to see if it loses vac over time. It failed twice now and is sitting over night again. Double checked all the connection and installed the high pressure switch on the high pressure port, it wasn't installed the first two times. I did install a new schrader valve in the high port. When initially I removed the high switch to connect the high pressure side to the gauge manifold the port had a continuous very slow leak of Freon. So a new schrader went in. The OEM schrader was kinda unique, couldn't find an exact duplicate for it but think the new one installed will do the job. But.

If all goes well should be able to drive the car Weds. Will dial the controller temp setting for the coolant temp first then adjust the A/C/fails safe fan speeds before charging the system with some fresh 12. I'm even entertaining the thought of driving the car to an A/C guy i know and have him put nitrogen in so I can be double sure there are no leakers. We'll see how time goes.
Don't think I can do the autox on Sat but is a possibility to make the local show in town Sat night.
Bob

#1071474 - 08/03/21 02:46 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Something the guys at work always said about Schrader valves is that they were never designed to seal a system, only to keep everything inside long enough to go from a cap to a hose and vice versa... They are also not nearly as good at holding vacuum as they are pressure, so putting a cap or a switch on it can make a significant difference, especially if that is they way it will be run in the future.
How much leak down are you getting when it fails?


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071475 - 08/03/21 05:00 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob, I'm glad everything it seems is starting to look up for you. This is definitely an educational thread and makes me think about how I post. A lot of the things I put in my build thread I put there hoping it helps someone like a lot of threads on here have helped me. I might start a tkx thread just so it will be easier for someone to find down the line. I feel like a lot of things might get lost in a build thread.

#1071477 - 08/04/21 01:14 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Good point on sea level, I did live in Maryland when I was taking that A/C class, was a few feet higher above seal level then. Hang in there, you'll get it finished!!


Leo Paugh
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#1071481 - 08/04/21 10:59 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob.....you make my head spin!!!!!! LOL


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#1071483 - 08/05/21 02:30 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Kevin, I think that's because you live at sea level.
Bob

#1071485 - 08/05/21 02:36 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Just a note about the vacuum level etc. At Lennox, vacuum level in psi or inches was only a passing reference (at the R&D lab and at the factory). The actual measured level of vacuum was in microns with a digital gauge, measuring how big the particles were rather than the pressure. That eliminates all references to ambient pressure that the gauge is referencing and makes a clean baseline all around.
That said, in the field, if there is reference made to microns it is usually with a chart that estimates microns based on pressure read from a gauge... And leakdown tests for vacuum would be done by pumping down a system overnight, closing off the valves and marking the vacuum level on a pressure gauge with a piece of masking tape, letting that sit as long as feasible (at least a couple hours, all day and check it the next morning if you had enough other stuff to do) and looking for a gap between the needle and the masking tape edge. It was an amazing balance of scientific method and measurement with just enough "Eh, that'll do" thrown in to keep it interesting...

These were also systems that held between 7 and 21 lbs of refrigerant, so the dwell times and pump times are quite a bit different from automotive systems.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071490 - 08/07/21 06:45 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Shawn the vac pump I borrowed specs at 15 micros, JB DV85N, surprised me when i looked up the specs. The system was evac'ed numerous times and sat overnight for most of them. Once I capped the high pressure port it held 12 hours at 18". I was happy with that. I did replace that high pressure Schrader, but as mentioned Schrader's are to hold pressure not vac.

Since getting the new Cool 125 controller on Mon lots of things happened to drag out the test drive until today, Fri. And as it would be the State safety and emissions inspection stickers ran out at the end of July. At 4pm this afternoon was able to get a couple new ones stuck on so I can be legal for the Sat in town car show. As of right now got fans, A/C and new stickers, time for some driving again.

Interesting week!.
With the new controller installed, instantly had a problem before starting the engine. Turning on the fail safe mode with key on IGN should fire both fans at highest speed. Only one fan turned on, *************!!. My Fluke VOM in hand went through all the voltage and wire resistance, checks, everything normal. Went to the control and did the jumped out the terminals to bypass the requests and temp sensor checks which should turn both fans on high. Same thing only one fan. Removed the Spal dual fans to the workbench and did voltage draw and ohms testing on both, ran both at full speed for 10 minute and did rechecks, nothing, they are good to go, not my problem .
Both fans have a GM (Delphi) Metri Pack 480 plugs, rated at 42 A.
Inspecting the male plugs on the fans i saw a shiny black tinge to the + on the problem child fan. Took the plug apart and terminal look good, no signs of overheating, other than that shininess of that male + pin. Now inspecting the female side of the fan plugs i saw the + on the problem child looked like it had got just a little warm, and damn the center tensioner of the terminal was slightly open, had lost tension. Taking the plug apart and what i found was losing tension it didn't cook the terminal, no real signs of arcing, burning, cooking the terminal. But it got warm enough to melt the nylon the plug is made of and put a very thin coating on the contact surfaces. The damage to the nylon plug was minimal and I was able to reuse it. Cut and crimped new terminals in that plug. Now both fans run.
The sad part is those plugs had voltage and resistance reading done numerous time by probing those terminals, always showed good. It wasn't until i took that plug apart did a see what was happening. Have seen many cooked terminal connection, this is my first where plastic (nylon) got into a connection and opened it. without cooking it.
That experience in stupidity for not catching that I chalk up to a senior moment. For a long while I sat in a chair and stare at the car saying " what the hell am I missing here". When you finally stumble upon it you realize it's another of those puzzles you don't need as your brain doesn't function as well as it used to.

Once I had that fixed the fans function was back to where it was at the start of all this. Doing everything correctly.
Now time to move onto getting the A/C charged and cold air out of the vents.

Out of time now but will go into more details about filling and tuning an A/C system later. With all the downtime of this project had lots of time to learn a little about A/C. Will leave that at Super Heat and Sub Cool checks I did today and getting 36 degrees out of the dash vents on a 90 degree day.
Bob

#1071496 - 08/08/21 01:01 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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thumbs


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#1071502 - 08/08/21 12:30 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Think that was the problem from the start Bob? Good catch and don't feel too bad about the senior moment...at least you were still able to find and fix the issue. laugh


Lance
1985 Monte Carlo SS Street Car
#1071508 - 08/09/21 04:25 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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It' hard to say at this point if that connection was the source, was it just added to or caused a problem with the controller. I still think the controller had a issue. When the controller was screwed to the rad support it had a controller frame to chassis ground and the sec fan would only run slow. When the controller was removed from the rad support, no chassis ground, the sec fan would run on high. Will see what Darryl has to say about the old controller this week. The overheating at that autox was most like only one fan running slow, not nearly enough air across the rad when beating on 2nd gear for 50 seconds on a 90+ day. This engine has never overheated like that. I knew there was something wrong that day. Just to stupid to find a simple problem first.

With the new 125 controller that is programmed a little different than the old 85 both fans now run on PMW. It was 90+ in the shop the other day while tuning the A/C, everything was HOT. At the rad inlet, it's painted rad black and is a copper/brass, using my pyrometer I was seeing 170 at the rad inlet and and 135 at the sensor in the lower rad hose. I thought that was a little low for all that time the engine and A/C was cranking for a half hour at a time. When the A/C calls for electric fans via the high pressure switch both fans come up to full speed. If A/C is off both fans were running about 50% with an engine that has been idling for a long time in a 90 degree shop. The 125 has a rotary switch for temp adjustment from warm to hot, has 11 detentes. I turned the switch up to two clicks before HOT and think engine temps need to be hotter yet.
I've made hundreds of 2nd-3rd pulls on this engine at WOT and know how it shows up on my stock dash temp gauge. This week is another cooker, 90s all week, and will now have time to go for some "drives" and monitor the engine temps and see if I'm happy with way the fan controller is controlling engine temp. Can shoot the rad inlet easily with the pyro. But may find taping my temp probe on my Fluke VOM to the rad inlet may be more accurate.

Something i also noticed was the temp at the rad inlet got warm quickly at engine startup from cold and stayed in the 155-160 range for a long time in the 90+ shop. It's been several years, maybe a decade, since installing that thermostat. It's a Stant Super Stat 180 degree 45358, with a 1/8" hole drilled in it. Thinking time for an inspection of the stat to insure it's closing all the way. Should see temps near 170 before the fans turn on.

Another possible issue is the sensitivity of the controller's temp sensor, thermistor. If out of range for the new controller it could effect how the controller adjusts the fan speed and when. When troubleshooting the old controller one of tests is thermistor resistance, new should range 0 to 50K depending on sensor temp. At 85 degrees it was 43K which I was told was in spec. Just something else to think about. And being the sensor is in the lower rad hose kinda a PITA to change, not difficult, just a PITA.

Drove the car about 25 miles Fri/Sat and at this point happy to be past the electric fan problem. With just a little tweaking it should be back in the set it an forget it mode which it was for near three years. That was why I had a AutoCool 85 in the car, never gave it a thought, it just did it's job well...... for three years.

On to the A/C side of this adventure, tomorrow.
Bob

#1071520 - 08/09/21 08:10 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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I'm waiting on ac adventure part.

Last edited by 88ssBrent; 08/09/21 08:10 PM.
#1071531 - 08/10/21 06:42 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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With limited time to play with the car the past couple days haven't had much time to get back to finalizing this A/C system's performance. I did do a cooling system fan operation check today and found the same results. The thermostat needs to be looked at. It takes but a minute of just idling at 850 in the shop and the upper rad hose is in the 100 degree range, and raising quickly. This the controller sees and fans are on slow at 135. Just think this is all to cold for fans yet. the thermostat does have a 1/8" hole drilled in it but that shouldn't contribute that much to flow when the thermostat should be closed. Inspection/replacing the thermostat will happen soon.

The A/C I'm very happy with it's performance, depending on blower fan speed temp 36-40 at the center vent are common. Actually very good. Cycling pressures are right in spec for what i feel they should be in the ambient conditions. The problem you run into is there is no real specs for these cars, just service ranges, low pressure compressor ON at 20-28, OFF 41-51. I come in at 26 and 46. When the engine is idling at 900 the low pressure is ranging around 36 and the compressor is ON continuous because the A/C control is set to MAX and the blower is at full speed. Dash temps will be 38 degrees give or take.
When the blower speed is turned to slow, the pressure will decrease to 26 and the compressor will cycle ON, runs to 46 and OFF. It will cycle the compressor ON off OFF 3 or 4 times a minute which I think should be 6 or so is better

Charging the system went rather smoothly, but not without a few clinches. Weighing in using a digital scale makes things easier but i think i screwed that up. The tank sits up side down on a scale, sits on a steel cabinet, a hose runs to the manifold gauges set hanging on the underside of the hood. You do the fill procedure per the service manual and add 3.25 to the system. the digital display told you that, 13.0 was the target. Several minute later after you've filled the digital say it's 3 oz less than 13. Why? Now your guessing how much went in, is it just a little over full?

That's when I thought I needed more knowledge about how this old GM R12 system should perform, now I'm relying on my gauges to monitor the system, not enough info to just rely on pressures. Being there is very little info on these specific R12 cars, you need to start with basics and try to guess at what amount of 12 in the system works best for me. With a lot more knowledge about A/C now and the tools have measured Sub Cool and Super Heat which was a learning lesson the first time last Fri. Pressed for time that day didn't take good notes but saw it was actually very good. With most A/C systems sold today, other than automobiles, somewhere on the outdoor unit will be the spec tag. Super Heat or Sub Cool or both will be specs on that tag. A tech can tune the system using those specs.

From all the confusing A/C classes I've watched on the web it appears because of the nature of this system, fixed orifice, electric fans running off a high pressure switch my concern and where I concentrate is the Sub Cool measurement. Sub Cool is condenser, basically making the condenser as efficient as possible. And that is adjusted by how much freon is in the system, which relates to pressure in the system.

The big eventually consideration in all this is evap temp and if it gets working to good you can frost, freeze the evap . When you see center vent temp dropping below 36 there can be a problem. This where Super Heat numbers comes into play, evap.

Haven't play around enough with all that to have a definitive answer yet. As i said the system may still be a little overcharged. Now that I can actually see all the real number with accuracy, and quickly, will be able to put specific performance numbers to R&R of this system. Again with very little "this is what it should be" numbers for the SH and SC it's a guessing game. But having them close to equal and in the range of 10 degrees or so seems to be the goal. First time it was 12.5 and 14.0.
That 14.0 SC is high and suggests over charged. The reason for playing with the freon charge until I'm happy.

Weds it's going into the mid 90s, a good day to play with the A/C. Will be able to drive it, get it hot hot under the hood and then back into the shop for testing to get a good idea how those SH and SC look.

When I did the change from 134 back to 12 in this car 13 years ago it was easy, charging an A/C system with 12 for dummies. Did the whole procedure correctly even weighed in the 3 1/4 lb with a digital scale back then. Took me an afternoon and I was throwing ice cubes out the vents, DONE.
This time somehow things got much more complicated, to much knowledge maybe.
Bob

#1071536 - 08/10/21 03:39 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Yep, sometimes the refrigerant in the hose can cause a swing one way or the other. If possible, you can shut off the valve on the tank and get the measurement after the hose clears or fills, depending on conditions, but that is rarely physically an option. Sometimes stringing the hose vertically next to (and higher than) the tank helps, other times, just minimizing the hose length is the best option. Sometimes in the lab we would charge with the smallest copper tube we could realistically use to try to minimize those effects (and the copper would get it to equilibrium temps quickly compared to regular AC hose). Chasing ounces of refrigerant in hoses can absolutely drive you crazy, and it seems like it usually ends up being "in the noise" and not affecting anything anyway.

The simple answer is always "Weight it in and don't go down the rabbit hole" on car systems. That said, sure, I'll join you to go look for rabbits smile

I think you have the basic idea down for sure. Subcool is your condenser performance, and how much margin of error you have. You probably aren't finding guidelines anywhere because basically want "enough, but not too much". Too much subcooling is generally overcharged, but you have to get pretty far on overcharge before you really cause problems and you will see it in high discharge pressures. Too little and you risk flashing the orifice with gas. Not a huge deal, just not great for performance or longevity (shock loads to any system aren't great) and your cold air has sudden bursts of warmness to it, and you can sometimes start cooling your liquid line from minor pressure losses. If you have 100% liquid in your coil that isn't subcooled any, then it makes a long journey on a liquid line and takes a sharp 90, that restriction drops the pressure a psi or two and now you are boiling refrigerant, soaking up heat from the hot underhood, and losing some of your capacity you already paid for. Not terrible, not likely, but it's a possibility.

You will get higher subcool on a cooler day than on a hot one, since it is measuring how well your condenser is removing heat. Basically the reason to want 10° is so you will have 2° in a worst case scenario. Having 14° on a normal day when testing the system doesn't seem out of bounds to me, especially with good electric fans. You can experiment and turn up or down your fan and watch the subcool number, it should go up with more fan speed and down with less air. Engine speed will also affect it, but its not as simple since it will change the refrigerant flow rate and pressure at the same time, which are somewhat offsetting in their effect. Theoretical ideal is 0° on the hottest day with the hottest evap temps and the worst compressor speed you will generally see, then you will get more everywhere else. That's not realistic to measure or to target, so having some under normal conditions and hoping it's enough for abnormal is basically the way to go.

Superheat is a little trickier (ok, a lot trickier) on a car vs your house. Superheat is making sure that your evaporator gets every bit of capacity out of the refrigerant that it can (making sure you boil it all off). Part of this is efficiency driven (you paid to compress it, you want to get the expansion benefit), but part is also because you don't want to return liquid to a compressor that is made to compress gas. Too much superheat is a sign of "Starving the evaporator", too little (or having evaporator subcooling) is flooding it. Flooded evaps are really great at making cold air since the entire coil is very cold, but aren't very efficient and can cause other problems.
Fixed orifice tubes are always harder to get superheat right, since you can only tune it to one operating point. Expansion valves on your house make it much more forgiving over a broad range of conditions. But the broadest range you can imagine in your house is nothing compared to what a car evaporator sees. 120° inlet temps on a hot day at startup, 20° inlet temps when running the defrost on a cold day, high CFM, low CFM, high refrigerant flow, low refrigerant flow... It sees it all, AND it is a relatively tiny coil. It can do about 5 tons of cooling from what, 10"x10"x1"? A 5 ton coil on the commercial units I worked on was about 40"x40"x3". That small size makes it even less forgiving.

That's why they install an accumulator in the engine bay (the filter/drier volume and geometry act as an accumulator, even if it isn't really called that). Everything goes through the evaporator, then returns to the accumulator and any liquid in the system has a chance to soak up some heat and boil off, keeping the compressor operating on gas instead of liquid. The cycling switch is basically trying to keep a little liquid, but not too much, in the accumulator at all times.
For performance, superheat is basically wasted coil area and a car doesn't have much coil to waste, so I'd say if you are getting any superheat before the accumulator (unless it is REALLY hot), that's probably not ideal. If you aren't getting any superheat after the accumulator, you have too much charge and are risking flooding the compressor. Checking it at the compressor inlet is the real test for that. Pressure should be similar as at the low pressure port, maybe 2-3 psi different as long as you have a new filter/dryer, so you can probably just use the temp for the low pressure reading to compare to the measured temp at those locations.

If you want to play with system design, you adjust the orifice tube size and charge weight to get the right balance of subcool and superheat at all of the locations under multiple conditions. If that sounds like a tall order, it is. That's why we had a massive R&D facility and 16 computer controlled test chambers with 50-100 data channels and 200 engineers, technicians, and designers working on simpler systems, and it still took a month to get a system configuration down AFTER computer modeling for setting upper and lower limits on what we should see...

Last edited by Hunter79764; 08/10/21 03:51 PM.

Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071540 - 08/11/21 01:27 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Shawn thanks for shining a little more light on a subject that is one of those things that require a lot of engineering and insight to understand the complexities of an A/C system.
As usual i tend to over think things and get caught up in the details but that what floats my boat. But know the end results are always in the details.
Also realize it not a perfect system and I'll need to stay with the tuning as the ambient drop in the Fall. It's about getting good, not the best, results over a range of ambient. Tuning for the worst case temps can be a problem when you want good cooling for the 70s.
When you have a little knowledge, some tools and the desire to learn something you took for granted it takes time to sort it all out.

Today stopped at Napa for a Stant Super Stat 45358, thought it would be a simple thing to get. Nope, no got, don't sell. Down the street from Napa is Advance, stopped there. Because I was there picked up an MotoRad Super Stat 5200180, stainless, 180 degree, never heard of them but looked like the best they sell, saved the receipt. Inspection showed it isn't the quality of the Stant, not USA, Israel.
Next was the local Pep Boys. Funny the manager waited on me and had just spent the day changing all the part numbers on 6 shelf's of thermostat. Pep Boys is now selling the Moto and getting rid of all the Stant products and part number system. A check of the old 45358 bin, no thermostat. Next stopped at Auto Zone and drew a big 0. Luckily all those parts house are right in town, isn't a 6 mile loop to hit them all. A good old Stant, ran them for years and years, wasn't to be found, and couldn't be ordered.
Time for a background check of suppliers. Seems Stant, and Gates, and several other products we love are owned for several years in the UK, Tomkins. It appears Stant is now re-branded as Moto for some of it's products, thermostat's in particular. This conglomerate of car part suppliers bottom line the products by out sourcing solely for profit. Quality suffers and the price go up, and money goes overseas.
Will now add Stant to the LONG list of manufactures gobbled up by a few huge hedge funds.
Rant over.

Tonight rolled the dice and bought a NOS, I hope, Stant 45358 for 14 bucks delivered from Rockauto. Might even have it by Thurs.
Having a new 180 Motorad and a new 180 Stant side by side, and even the old 180 Stant I'm removing will get a good look at father time.

Just to add a little more to the mix i tried running a Robert Shaw 180 "balanced sleeve" thermostat recommended by Steward water pump. That was in the engine when it fired up new. For some reason which evades me I removed it and installed the Stant soon after the breakin. This is that thermostat.
https://flowkoolerwaterpumps.com/products/robertshaw-330-160-degree-thermostat?variant=9125073322036
I may still have it stashed away some where.

Also ordered a Gates 7570 A/C belt at Pep Boy while there, coming from another store 40 miles away. Picked up a Napa A/C belt, 7570 at Napa today, they had trouble locating a Gates for me. Need to be sure those belts are identical. Had issues with the A/C belt at startup. ran a Gates 7570 for many years before the R&R of the A/C. A new Gates 7570 was to short. Installed a Napa 7575 (1/2" longer) and it was tensioned at the center of the adjustment slot. It squealed, more tension it squealed, again, again, now out of slot. Went back to the old used parts box and installed a used Dayco Top Cog A/C belt from 10 years ago, center slot and no squeal. Go figure.
Did i mention Stant and Gates are the same people?
Bob

#1071550 - 08/12/21 04:00 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob, its interesting that you brought up the parts conglomerate. I just saw today where a Wharton Automotive Group acquired Silver Sport Transmission.

#1071600 - 08/14/21 06:06 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Wharton is Paul Lee, owner of McLeod and FTI racing trans, now Silver Sport. Which used to be Keisler. This may be a positive move for the community, he looks like a one man show at this time.

It's been in the mid 90s here and not much ambition to spend time in the shop.

New Gates A/C belt length I need to install wasn't going on easy. Had to remove the compressor two adj bolts from their slots to get the belt on. Then was able to adj belt tension to near middle of the adjustment slots in the brackets. Started engine and got no squeal when the compressor was engaged. So for now belt is on, will put miles on it and see if it tension changes as the belt wears in. I still think something changed on the Gates belts, from a 36 to a 37 degree. Funny when I looked at Gates belt specs catalog it says 37, when I look at the Gates Australian belt catalog it say 36 and Rock says 36. The Dayco A/C belt is listed as a 36 for that application.
Now past the belt thing and need to move on.

As it would be the Stant 45358 I bought from Rock arrives yesterday. It's a Motorad 1500-180 thermostat in a Stant box with a sticker over the old number and both the old Stant and new Motorad number on the box. So much for that. Is the Motrad a good thermostat, don't know but quality appearance is not as good as the old Stant pulled from the engine. Did I mention the Rockuto price for the thermostat was $3.94 +ship and tax. 3.94, what's the markup on that.

In my stash of old part there was a brand new Delco 10207381, 180 degree, thermostat bought more than a decade ago. It was placed on the bench next to those two losers.
Thurs evening drained enough coolant and removed the old Stant thermostat, it was 100% closed which it should have been.
Oh, I remember now instead of a small hole drilled in the thermostat to bleed off any trapped air when the thermostat is cold and closed there is three .187" (3/16") hole drilled in this one. This was done as part of the tuning for the old Spal fan controller I ran for 10 years. That controller temp sensor was in the thermostat housing on the rad side of the thermostat. The sensor needed hot coolant flow there to help the controller get the primary fan up to speed earlier. Also the Dart engine block i run doesn't have a bypass hole in the block for the water pump, unique to Dart blocks. That makes coolant circ when the thermostat is fully closed less.
And as another contributor to seeing hot water in upper rad hose to early (thermostat closed) is a 1/4" stainless coolant line runs from the back of the cylinder heads to the rad side of the thermostat housing. This Dart block has Siamesed bores with no stem vents needed in the heads between cylinders. Me venting the back of the cyl heads may help vent trapped air, can't hurt anything. So in total four 3/16" thermostat bypass holes flowing past a closed thermostat.
With my new fan controller setup the rad was seeing a lot of hot water coming through those four holes. The engine was struggling to get up to 170-180 operating temps under normal driving.

So today the Delco thermostat had only one 1/8" bleed hole drilled in it and installed. This engine was run several times to purge air from the system. What you drained out should go right back in, but on this engine it never does, still close to a qt to dump back in. You need to hot/cold cycle it a couple times and put a few miles on it with heater ON. That will be done tomorrow. Today it was 95 with an index 100+ index, hard to get interested in that test drive..

Also plan to get accurate numbers written down on the specs/tune of the A/C system this weekend. Need to know the fans are doing exactly what they need to do and be done playing around there first.
Getting close to closing the hood for a while. Two weeks until the KOTM trip.
Bob

#1071669 - 08/18/21 06:22 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Well the test drive on Sat bombed. A 3 mile trip around the block with some 55 mph and the temp gauge was going nuts. Idling was good, about 180 degrees, out on the highway the temp gauge was 190, then quickly 225, then back down then up again, not boiling hot just never had a ranging problem like this before.
Had the pyrometer with me on the second quick trip to shoot block and heads and was seeing 225. As soon as the car was stopped i jumped out and checked temps while running.

Back in the shop now looking for anything other than what I think the problem is. A timing light showed to much initial advance, 22 degrees. 17 is what is set. A lot of advance is run in this engine. 17 initial, 37 total with a 19 degree vac advance. It's a lot of timing at 2300, about 52-54, but what the engine likes and needs for economy at 70 mph. If the initial is 5 over that puts cruise timing in the high 50's. Usually lots of timing on light load tend to cool the engine. Can't see how all the timing relating to running erratically hotter.
Looking for a reason for the+5 degrees initial pulled the cap and rotor to look at the centrifugal in the Pertronics HEI. Several years ago had a problem there. One of the pins broke the weld and was laying over, had it TIGed and fixed that problem. So was looking for another possible problem with the centrifugal. Weights, springs, pins, everything is good. But look under the rotor and notice the weights are rubbing the rotor. HUH. Pulled a couple old rotors laying around and saw no where a touching of any kind. Did some measuring and found the rotor's mounting surface was a little bit different from those old quality rotors. The condition and quality of the cap and rotor are very good, phasing is great, reuse them. To clearance the weights a fiber shim of .037" was cut to fit the mounting tabs and this lifted the rotor up for weight clearance. Time will tell how that works out. Next put the timing light back on and see if the timing was effected by the weights contacting the rotor and not allowing them to return to zero centrifugal advance.
If not will reset initial to 17 and go from there. It's unusual for the timing to advance, as things wear timing retards. Did the dist move, advance, I doubt it.

With 4 different thermostats, old Stant 180, two new Motorad 180 and a Delco 180 they all went to the kitchen stove to get cooked. The old Stant started to open over 190 and slowly until full open at 205. The Motorad where a little over 180 and full open at 192, the Delco 183 and full open at 195. I chose to put the USA Delco back in the engine. I would say the old Stant that was in the engine for a decade was out of spec.
Had drilled a 1/8" hole in the Delco before install for the last test trips in the car. The previous Stant had three 3 /16' holes in it. I attribute some of my last overheating to only an 1/8" hole. A Dart block doesn't have the 3/8" coolant recirc hole at the left side of the pump mount. On a normal SBC when the thermostat is closed the pump pushes coolant into the block, that 3/8" recirc port feed coolant back into the suction side of the pump. A Dart bock with the thermostat closed has no recirc until the thermostat starts to open. By drilling three 3/16" holes in the thermostat plus the 1/4" tube dumping coolant to the thermostat housing that equals closely the flow of that 3/8" recirc hole in a SBC. The down side to that is engine warm up takes much longer due to the water to the pump is now is coming from the radiator, cold. It's just something i need to live with.
So the Delco thermostat now has three 3/16" holes and is in the engine.

Now the real PITA. What it boiled down to is an entrained Stewart water pump. When this engine was being fired up for the first time a Stewart water pump was installed. I fought with coolant non-circ for a month trying to figure out why the pump wouldn't just pump and get water moving like every other SBC I filled up with coolant and drove away. Numerous calls to Stewart tech, tried raising the front of the car 2 foot higher, back of the car, nothing, just wouldn't circulate. After weeks I finally bought an Edelbrock pump and the first try water is circulating. Sent that Steward pump right back to the Stewart tech for checking. They sent me a new pump but said nothing was wrong with the old one. Well a couple year later running 110+ though the traps the powdered metal Edel pump impeller blows up, pushed the plate off the back of the pump, left my car sitting in the pits until the next day when I could trailer it home. Not happy.

Now with a Stewart that doesn't pump, and Edel that blowd up ordered a Weiand Team G. Stamped in the rear cover in huge letters CHINA. Back in the box and returned. A stock cast iron out of the question. So pulled the new Stewart that they sent me and I need to make this work. Well it was a lot of aggravation, but an elaborate mix of hoses and pressure forcing coolant through the pump and it pumped. What happens is air gets trapped in the top of that pump and no way to get it out. Forcing coolant at pressure was able to dislodge that air. Pulling the rear covers on the Stewart, Edel and an old junk cast iron pump you can see how it can get trapped in the larger open space of the Stewart. I'm pretty sure air entrainment is the problem and added to that the Dart block has no recirc to the pump that may help move that dead air.

Air in a pump greatly reduces it efficiency,, and as rpm increase efficiency is reduced even more. I believe the reason for the coolant temp to sharply rise and fall at different rpms.
And also knowing even after two heat and complete cool down cycles there was still 6 oz sitting on the bench that needed to go back into the system from the draining. Almost positive it should be in the pump

Knowing a little about vacuum filling a cooling system i decided that was the next step to get this car back on the road. After looking at numerous vac fill tools, videos, was set on being this one. Don't need 25 adapter for different rads so a simple kit that fits most of what I work on will do. And it's made in Canada, go figure.
https://www.matcotools.com/productassets/web-documents/AC550000_PartsBreakdown_01.pdf
Before buying one and waiting three days or more for delivery I stopped to see a mechanic friend this afternoon. He said the one he has he got from Matco about a year old and was never used. He pulls it out of his cabinet and it's exactly the one i was going to buy, and, take it with you and see how it works.
Had a little time to play with it today and sucked in a coolant charge but stupid me forgot to open the heater valve. Ran out of time but will be at that again tomorrow. It's really slick the way if pulls the coolant into system. There just a few particulars to pay attention to but once you have the knack it's stupid simple.
I'll eventually buy a 540000 for the future.
I'll know in short order if it works as expected because all the coolant removed will put the overflow tank right back at the cold fill mark if everything goes well.
Hoping for a test drive tomorrow with no temp gauge dancing.
Bob

#1071674 - 08/18/21 03:07 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Very interested in this as I have a neighbor with a SBC in a Chevy II that has been fighting an overheating issue all summer and we can't seem to find the cause. I keep coming back to his water pump as well, almost HAS to be that. He has a Eddie Motorsports front runner kit on it and I was convinced it had the wrong rotation pump installed...but an air pocket in the pump would also explain his strange over heating issues for sure.

His seems to be fine under most circumstances but once a load is put on the engine, it starts to heat up and never cools back down again. It'll idle in driveway in 105* temps with the AC on high for an hour and be okay, 7 minute drive down the road under load and temps start climbing and never recover...


Lance
1985 Monte Carlo SS Street Car
#1071675 - 08/18/21 04:54 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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I'm guessing you have checked the thermostat? Is it possible that it is slowly opening, sticking in place, and not opening the rest of the way? Just a thought. It's a head scratcher on both for sure, the air bubble in the water pump seems to make sense.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071708 - 08/20/21 06:31 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Lance you didn't mention what pump, block, fans, radiator are in the car. Assuming the Eddie is a serpentine setup.

Well after sucking a vacuum and filling of the cooling system 4 times with the AirLift 520000 i figured just how to do the correct procedure to get the pump and rest of the engine 99% full. With this engine/cooling system it's a little tricky. First two times it was just for the fun of it and made mistakes. Third time I was thinking a little bit more of the drained coolant should have been sucked in. 4th time I plugged the Mighty Vac into the hose coming from the Vac ball reservoir and applied 15" to the vac system to the heat/A/C control to insure the heater flow valve remained full open while filling.

Because the rad cap is on the side of the rad you can't get the top of the rad full, an air pocket will still be there after refill. That air is removed as the coolant cycles through several hot-cold cycles. Eventually the coolant overflow will put the rest of the coolant in and remove the pocket of air in the top of the rad.

Weds night after the 4th refill started the engine and let it idle until running temp, 180. Several years ago installed a bleeder Tee close to the exit of the heater core. The logic was that is the highest point in the cooling system. After extended idling with the heater on, opened that bleeder and still had air trapped in the hose. A steady stream of coolant should come out of that bleeder when the system is under pressure, nope. Hmmm. Turned off the lights and went home.

This afternoon checked the coolant level in the reservoir, it had gone down about 1/4", good, top of rad is near filled. Out for a 3 mile trip around the block watching the temp gauge. Cool, it's now steady, no ranging between 190 and 225, steady at assumed 185 via a pyro on the temp sender. Idling back in the shop and it now a steady stream of coolant out the heater hose bleeder, good. Let it cool down and checked tonight, 1/4" below the full line in the reservoir. GOOD. I figure once all this hot-cold thing finishes the 100% full system it's done. I will need to add maybe 6 oz for the coolant i lost due to all this draining and filling of the system. Stuff left in hoses, buckets, filtering, splash when draining, results of 4 vac fills.
BUT I DO THINK THE SYSTEM IS FINALLY FULL, no air in the pump..

Tomorrow will drive again to get engine hot before going back to tweaking the A/C system charge. Thinking I may be back to normal with the cooling system and electric fans doing what they should.
Today was another 92 degree day, was seeing 190 ish at the temp sender, 178 at the inlet to the rad and 135 at the fan sensor in the lower rad hose. Those rad temps are what I saw before all these problems started months ago. That's a 35 degree drop across the rad, dual 11" Spal fans are doing their job.

Today I called Dart tech to get an answer about why no coolant bypass in their blocks. The answer i got was the block was designed 20 years ago and that engineer is gone now. OK. But we both think it's because of the amount of cast iron around and to the front of #2 cylinder for strength, the .200" think cyl walls and the fact the block can be bored to 4.185 without problems.

For now done with the recirc thing and know the four holes (three 3/16"in the thermostat, 1/4" tube from the intake at #7 and #8) provide close to equal volume for recirc. But slow warm up is the end product. If another water pump would go on I would plumb a 3/8" line from the heater core supply hose and dump it in the inlet of the pump to create a better recirc loop. Not really difficult to do. Hindsight. Could then not have to have all those holes in the thermostat.

Cleaned up that brand new Air Lift tool and returned it along with a 1/2 dozen tomatoes and some jalapeno and habanero I picked fresh from my garden. He said BLTs where on the menu for dinner now.
Next week will order one of those AitrLifts for my tool box. Great, high quality tool, make refill easy once you have the technique down.

When I charged the A/C system 14 years ago I looked for a Tee for the high pressure port so my gauge and the high pressure switch i use to control the fans could be used on the port at the same time. No luck. Last week ran across a Tee and it's now sitting on the bench ready to use tomorrow. It will make watching how the high pressure switch and the electric fans interact while watching the gauge, real time monitoring now. As mentioned the high pressure switch turns the fans on and off, not clutch activation.

Next Fri the car makes the trip to the KOTM event, a 550 miles round trip, a good test drive to see if the cooling and A/C systems are working properly. Cutting it close but thinking we're good to go.
Car prep for the trip is just a matter of install the the old 16" wheels and tires and saving the new 17" wheels and RT660 tires for two autox event i hope to be able to make this year yet. Also don't have a lot of confidence in driving that 660 tread pattern (or lack of it) in the rain at 70 mph which is most of the 550 miles. Last years trip to KOTM was the first two hours in pouring rain.
Bob

#1071715 - 08/20/21 04:15 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Glad to hear you have everything straightened out. Im willing to bet your temp will stay at a nice even 180° and the ac will be blowing cold for your trip to KOTM.

Last edited by 88ssBrent; 08/20/21 04:15 PM.
#1071716 - 08/20/21 04:24 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Good work Bob! Can't wait to see you next week!

My neighbors car has an aftermarket aluminum radiator that we think is the culprit. It's a downflow type and the drivers bottom portion of the radiator is 40-50 degrees cooler than the whole rest of the radiator. The outlet portion of the radiator is the same temp as the inlet, basically the water is just flowing around the outside edge of the radiator instead of through the whole thing.

We've verified the water pump is pumping the correct direction and actually will suck the lower hose in when a restrictor is put between the lower hose and the radiator...the pump is working as it should.


Lance
1985 Monte Carlo SS Street Car
#1071724 - 08/21/21 05:59 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Back in the early 70's the toy was a 62 Nova with basically a 69 Z28 drivetrain, roller cammed of course. The radiator and fan shroud was the 4 core copper brass from the 69 Z, with the technology of the day a Flex-a-lite fan and the proper spacer. More than enough for that little mouse, that roared. That Harrison Z rad was a crossflow.

I thought downflow rads are for vintage stuff that doesn't fit crossflow well. My brother-in-laws 39 Plymouth, old 357 hemi and a big blower has a down flow because that's all the fits. He's has had his share of fun trying to keep that engine cool.

Assume electric fan, fans, proper coolant ratio, is this an A/C car,? Shiny alum parts are hard to get an accurate pyro reading from.

It took two flex fan failures to make me never use one again. First was in the Nova at the drag strip, a blade came off and struck the sending unit for my Super Sun tach killing it. Luckily the S&W parts trailer was in the pits and had a sender. back off to the races. Costly day but didn't pay that bill until a few days later at the speed shop. Second failure was in my 69 C10 with a fresh 350 mildly build, stick shift. A quarter of the way out on a 2000 miles round trip vacation, think I was looking at Ohare on my left, a blade flew off the Flex-a-lite on that engine. Found a speed shop in Minneapolis, only available thing was another Flex-a-lite, my very last!.

Enough about the fun days.

It rained today, very short trip round the block between rain drops to get engine hot. Temp gauge showing about 180-185 steady, no wandering all over the place anymore. A long extended idle period while playing with the A/C and very happy the cooling issues are done. Tomorrow morning ends another cool down cycle, should be all done with that and will measure in a quantity of new coolant to bring it to the line on the tank. Should be about 6 oz to replace lost coolant while doing this fiasco.
Using the pyrometer on header primaries, heads, block, even directly on the gauge sender when the engine is very hot can give you good info. Wish I had a pyro 30 years ago.

Forgot to mention, after seeing 5 degrees more initial timing at 600 rpm and finding possible interference between the centrifugal advance weights and the underside of the rotor, shimming the rotor up .037", the timing was back at 17 degrees on start up. Maybe my fault. The ignition is a conglomerate of parts. A Pertronic dist with a Comp Composite gear, advance weights are GM HEI, cap/rotor/coil are DUI, vac advance a speced unit, no module just a pickup feeding a processor in the console which takes care of dwell, rev limiter and knock retard.
So fixing that +5 advance problem required attention. But it was several years since last looking, checking those parts. But all is well now. Even checked the idle fuel pressure, idle vac, timing, advance rates, idle A/F, carb screws and bolts, vac lines, hose clamps, all those PM things you need to address periodically.
Never would have thought weights hitting the rotor was a cause if i didn't clean the bottom of the rotor, and having my reader glasses on.

First round of A/C checks didn't go well. It works good for a 90+ day but need to get vent temps back below 40 degrees. One thing I did learn is when the hood is up, it leaves a clear path for hot air to enter into the fresh air intake, pass side of the cowl, for the heated air to influence evap performance, dash vent temp. With gauges connected it hard to close the hood as recommended in doing performance checks. Sitting in the shop idling and driving down the highway

Checking Super Heat requires reading freon line temp at the inlet of the evap. I use electrical tape, bury the tip of my Flute temp probe against the tubing and get an accurate reading for Super Heat. Then transfer the probe to tubing just ahead of the orifice, tape it down and get a Sub Cool temp. Problem is frost on the evap inlet tube doesn't allow re-taping the probe, no stick.
Need another Fluke probes so the one on the evap inlet can be left in place. Have a digital bulb thermometer but difficult to get a good stick on the vapor line.
So still working on getting accurate number on whats going on and how Super Heat and Sub Cool tuning impact system performance. The specs for the stock system in the Helm's Service manual are not operating system perf specs, but just ranges for a tech to say "good to go", "can't see it from my house".
Finding credible info on an old GM R12 system is all but non existent. If some of you remember, "A/C isn't as good as it was last year, stop at the Boys and pick up a can of 12. Add until you see the accumulator sweat." There's so much more to it.

That Tee to use on the high pressure port i bought doesn't fit. The high pressure port is 3/16" thread, not 1/4". the high pressure switch is 3/16". I use an adapter hose from 3/16" female to 1/4" male to attach my high pressure gauge hose, 1/4" female. Sorry about misinformation. The adapter hose is Four seasons #59600 which I see is all but extinct.
Bob

#1071743 - 08/22/21 05:41 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Had a little time today to spend with the car. Put the gauges and temp probes on the A/C to see if i could dial in a Super Heat and Sub Cool and get this thing done.

First checked the coolant reservoir when cold, it was lower than yesterday. More coolant is now back in the system and should be close to no air anywhere. The top of the rad is one of those places where a little air can be trapped until several heat-cool cycles removes it. Now was a good time to top off the reservoir to the full line, 8 oz was added. That's about what i thought should be added to make up for lost coolant during all the draining and refill done. Will check again but think good to go now, no entrained air in the system.

Again 92 in the shop and engine idled for a long time while watching the A/C running at max and engine temp I was happy with. Rain, hurricane coming through on Sun, no cars and coffee for a test drive tomorrow morning.

A quick version of the Super Heat number is liquid temp into the evap verses vapor temp out. Temp out is a fixed number derived from freon type used and the low pressure gauge number. Temp in is the temperature of the freon liquid going into the evap. The difference between those temps is Super Heat.
.
Sub Cool number is how much high pressure vapor is turned into liquid in the condenser. The temp into the condenser is derived from the freon type and high pressure gauge number relation. Temp out of condenser is a measured at the outlet of the condenser tubing. The difference between them is Sub Cool.

So with gauges on the A/C and a temp probe on the evap inlet time to play with Super Heat. I know from the other day Super Heat degrees was way to low, and frosted the alum tube at the compressor. That is a big NoNo , can't have any liquid going to the compressor, shortens it life quickly. That's when i went home on Fri, rethink the process.
Today removed some of the freon first thing, overcharged, and got the Super Heat temp up to the 10 degree neighborhood. Being there is no spec for what that number should be it's a guess and trial and error watching how the evap reacts to changing Super Heat caused by low pressure change and watching the vent temp as an indicator of evap performance. I think the trick is paying attention to the Super Heat as the system low pressure varies. It will range from 10-12 degrees Super Heat as the low pressure changes when the compressor is cycling on and off. Being the car is sitting inside, 90+ degrees, hood up and a lot of heat around the engine getting a real world numbers of driving the car is not possible. Yes very long hoses and tempo sensor leads and you could bring them inside the car to view while driving, but.

A check of the Sub Cool and I was in the 10 degree area, and it will also vary as the high pressure changes during cycling. So close to a 10-10 balance right now, the proof will be out on the highway to see if the vent temps are acceptable. Had 42 at the vents with some 100 degree outside air being sucked across the evap coil while cooking in the shop.
Have read, and viewed numerous school "classes" on line about balancing an A/C system and optimizing performance. But there is a delicate balance and automobile A/C may be the most difficult because it's literally a moving target. Residential A/C is easier, it doesn't move and they tell you the specs for Super or Sub at a given ambient making it easier to dial in a correct charge.
Bob

#1071751 - 08/22/21 06:43 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Just ordered one of these for the next time the coolant filling frustration happens. Price is very good from these people. The Matco man is 200 bucks with taxes.
https://www.jbtools.com/uview-550000-airlift-cooling-system-tester/
Don't usually recommend tools but quality and function were excellent.

Looked at several other vac bleeders sold for much cheaper but plastic and of course over seas quality. Harbor Freight is 1/4 mile from me, that was my last resort before borrowing the 550000 I used the other day. Luckily a friend mechanic saved the day by lending his 550000, and I didn't spend 80 bucks at Harbor.
Eastwood is a 1/2 mile the other direction, sell this, no need for all those adapter and pay that price.
https://www.eastwood.com/astro-pneu...acuum-type-cooling-system-kit-78585.html

With all the times having problems with filling this engine and the many times I've filled other engines this tool will pay for itself.
Bob

#1071755 - 08/23/21 12:39 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob, I have to say that your thread has made me read and watch more ac videos than I ever thought I would. It really makes me want to dig in on mine but as I said in my build thread that is going to have to wait till next spring. Im just glad you are getting everything squared away. I know you pride yourself on downtime and this go around has been a doozy.

#1071762 - 08/23/21 05:53 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Part of all this is that I'm not cheap, just don't like others doing what I can do myself. In the near future going to install a split A/C system in the house and need to have a better grasp of what's involved. I hear some install prices and know material is 1/3 the cost, and seeing rain downspout hanging on the side of the house doesn't say quality. So even though I've been around commercial A/C for decades and working with techs you just never do get the big picture, knowing why it works requires a little education. Had done three different car A/C system R&R prior to this last one, and just did them by the book not knowing the why, just the how. All were successes. But this last one became a little more complicated because A/C failure was caused by a Sub Cool problem, the fans and controller issue.

Downtime is a big deal for me especially in the prime time of the car season. Every year I try to drive it 2000 miles minimum to have a reason to own the 86. Last year even in pandemic mode managed 1875. Next weekend will put near 600 on the odometer going to KOTM. That will be a good road test for the recent cooling, A/C problems.

Yep lots of good video on A/C, lots of not so good also. But hard to find anything specific about old car A/C, except the 12 to 134 conversions. Lot of "how", but really no "why" of how to tune an old car system. Even less on a old fixed orifice 12 system. So for me it's a live and learn, trial and error approach to put a tune on it so I can live with for the next, well, hopefully decade. I hate doing thing twice.
Bob

Last edited by mmc427ss; 08/23/21 05:56 AM.
#1071768 - 08/23/21 03:21 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Couple of thoughts on the AC... On your superheat, are you measuring Evaporator superheat or Suction superheat? i.e., are you measuring the temps on the line pre-accumulator or post? If you have 10° pre-accumulator, that's probably low charge and you will have tons of superheat at the compressor, where it actually matters. Another term for the accumulator is a "Superheater", as that is it's main job on an auto AC system.
The her thing is using the blower on "Max" setting with windows down and possibly passenger door slightly open to get a steadier evap inlet temp without picking up all of the hot air from the cowl. You can also make a shield from cardboard and/or foam pool noodles to get the flow a little less hot.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071788 - 08/24/21 02:22 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Thanks Shawn.
It hard to say how much hood up, 95 degrees in the shop, and all that engine heat influences the fresh air intake in the cowl. Supposedly when in MAX it's recirced cabin air, no make up. But would think some of that super heated dry air is being sucked down the cowl intake.
Just for fun I'll see if a piece of paper gets sucked to the inlet.

Measuring with a bulb right at the inlet of the evap, multiply layer of electrical tape to hold and insulate it.. Feel that's getting accurate temp. Using the PT numbers from my fresh set of gauges, zeroed, on the low pressure port on the accumulator.
When I first started to play with charge at first it was the hand method, warmer evap outlet than the outlet. Next it was the pyro but shooting silver, alum, isn't reliable. Tried black tape and wasn't going to rely on the numbers. Painting a small area flat black would probably be ok.
For Sub, bulb temp sensor taped to alum tubing just before the high pressure port, using PT numbers from my high pressure gauges.
Decided do my best with the PT numbers taken at the low pressure port and the bulb on the inlet. Because there are so many variable.

Or maybe should I buy a second bulb temp sensor and have one on the inlet, one on the outlet of the evap and ignore the PT charts?

Is it fair to say on these cars you shoot for Super heat that gets the most out of the system then back off a little to protect the compressor. The condenser side of the equation has so many variables to deal with as far as temp and airflow. Sitting at a red light or running down the highway at 70, 95 ambient or 75, engine compartment temp. Not to mention engine rpm and compressor rpm. Now make it an orifice tube system and just makes all that more interesting.

Most of what I've seen and read says orifice, deal with Super, TXV deal with Sub. An orifice system is harder to make right because of the fixed orifice, a TXV will adjust flow according to outlet evap temp. Didn't the old, 70s cars, use a form of TXV?

Still have the same questions. On this 12 system what would the range of Super be, and can you assume you want the Sub and the Super to be close to balanced, say 10-10. I understand condenser flooding and the same with the evap. With so many variables where is that happy medium.

Saw this digital pressure- temp gauge set demoed. Pretty cool, would think a stupid person could tweak a system with it.
https://www.trutechtools.com/Fieldpiece-SM480V
Bob

#1071791 - 08/24/21 04:43 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Man, that gauge/thermocouple/scale combo unit sure would make life simpler. One tool to do it all... But $600 is a little outside the range I can justify to avoid juggling gauges and probes etc. Maybe one day though. If you can get a clothes pin or even just a zip tie to hold the probe in contact with the tube, that should get you pretty good numbers. Bonus if you have a little square of foam insulation, put that over the top of the probe and hold that down on the tube with some kind of pressure. You get good contact, and the insulation keeps the reading from being as affected by the air around it.

It's generally safe to assume that you will have the same low side pressure pre-evap, post-evap, and post accumulator. Realistically there's going to be a psi or two lost, but not enough to worry about. The temperatures between those spots will all change quite a bit though, and that is exactly what you are looking for. The superheat measurement is going to be the difference between your saturation temperature that you read off the gauge for the pressure you are running and the measured actual temperature off of your suction line, either before or after your accumulator. If you are wanting to tune your orifice tube, you would probably want to measure between the evap outlet and the accumulator inlet to pick your orifice or tune the charge. But for a given system and making sure you are protecting your compressor, superheat at the accumulator outlet is what you need to focus on, as that is the only thing that matters to the compressor.

In other words, I would expect near zero superheat before the evap, because the liquid should not really be boiling there. If the evap is filled with liquid and you get a couple degrees superheat after the evap (basically zero), that will get the most bang for your buck out of the small evap, as the liquid pulls more heat than gas.
And after leaving the evap, the accumulator is going to soak up heat from the engine bay and boil the rest, and the piping is made such that it should only be pulling from the top where the vapor is, so if you don't have any superheat there, you are washing down the compressor.

And to repeat myself a different way (my wife loves it when I do this) but with numbers, If you have 0° after the evap and 10°+ SH at the accumulator, you know that you are maximizing cooling at the evap but aren't flooding the accumulator and you have a fair amount of headroom before you do for differing conditions.
If you have 10° after the evap and 40° after the accumulator, you can add more charge (or open up the orifice size) to flood the evap better.
If you have 0° after evap and 0° after accumulator, you are still returning liquid to the compressor and it will not be happy for very long like that.
All of these are based on having essentially 0° at the evaporator inlet. If you have 10° there, you are not getting near the capacity that you could.

That trick of making sure the outlet is warmer than the inlet is based on trying to measure the superheat change across the evaporator by hand, which works in a pinch to make sure you have a good column of liquid into and out of the orifice tube while avoiding overcharging. TXV's give better operating ranges as long as they have liquid feeding them, and the way they work is by maintaining a set superheat. Based on that, they will always shoot for say 6° superheat, so you have to make sure you have enough subcooling feeding it, otherwise you could be way off on performance and not know it just looking at superheat. Fixed orifice has to be charged so you don't wash down the compressor for any given size, so you charge based on superheat. If you don't like the rest of the system numbers, you change the size in the design stage. You SHOULD be able to get a size that works well with the superheat, supcool, and capacity all balanced, but only one of those will destroy a system so that's why you want to look at superheat the most.

And for reference, we always considered superheat and subcool as +/-2°, even in a lab condition. Sometimes you read the gauge a little off, sometimes your gauge location and your temp location is just far enough away to affect it, sometimes the refrigerant specs are a little different from book value, etc.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071792 - 08/24/21 04:56 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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I should add, that is all theoretical, and the actual superheat numbers to keep your compressor alive is the charge that keeps gas and only gas going to your compressor under all conditions. cold weather, hot weather, high engine speed, low speed, high blower, low blower, etc. I'm thinking you would want to verify some superheat on max setting, low blower speed, on a 75° day at higher engine speed, I THINK that would be a reasonable worst case situation, and having a degree or two there should be enough. At 95° and blower on high with fresh air at idle, you might see 30° superheat after the evaporator on a good system, I don't know. But for reasonable charging conditions, warm day with fan on max and high and engine revved to 1500-2000 rpm (how everyone says to charge an auto system) ought to be a good baseline for comparison.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071826 - 08/27/21 05:30 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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It's been a couple days since last update. Tomorrow morning 8 am the car is making the 250 mile trip to UMI KOTM event. Have been to the first one, the second one and now the third with the 86 making the trip. This one is a little special, will be meeting Lance in person for the first time. And to top that off Kevin, (Crusher) and Frank, (Frank OC), all Forum member here will also be there, and we are all in the host hotel, and Frank will have beer. Should be a special weekend.

Weds was another hot, 99 index, day. A good day for a 30 mile trip around the block to see how the cooling system and A/C system behave.
The cooling is now full with the help of the AirLift vac refiller. Coolant level in the reservoir has maintained the same level when stone cold.
The temp gauge reading was steady, no wondering, showing a little warmer than before all this started but with the pyro saw 190 at the inlet to the rad. And that was under the extreme conditions, 100 degrees and A/C running the entire time, underhood temps were cooking.

A brand new AirLift 540000 was delivered on Weds. Should never need to be frustrated on filling this engine with coolant again.
Also have a good idea on how to get recirced coolant back to the pump when the thermostat is closed. Dart blocks don't have recirced coolant feeding the water pump, no bypass hole in the block. The only time a Dart block gets recirc is when the heater valve is open. A SBC with a heater has hot coolant out of the intake to the heater, cooler returns from the heater feeds into the pump inlet. Connecting the 5/8" heater supply to the 3/4" heater return with a short piece of 3/8" hose will supply bypass coolant to the pump and close to equal what the 3/8" bypass hole in a SBC has. The only downside is maybe the heater will be a tad less efficient but i doubt it. Not a big deal to make two brass Tee's to do that install, certainly can't source them anywhere.
The other benefit to adding that bypass would be the three 3/16" holes in the thermostat to produce bypass flow won't be needed. Would only need an 1/8" hole to bleed air then. Without the holes engine warmup would be faster and the 180 degree thermostat will be more in charge of maintaining temps under 180 degrees by staying closed.
So maybe another mod for the cooling system, but not needed right now.

Well A/C, the short of it is I'm not satisfied. System works and is withing the ranges show in the shop manual but know it could, should be better. The extreme ambient temps the other day on the test trip was a good test. Running on MAX and blower on high the best i saw was 42 out of the vent. At cruising speeds average was 44-45. I expect to see 40 and a tad lower 38-39 under idea conditions. Will be using the A/C a lot this weekend an will also see a lot of 50-70 mph driving. The little A/C thermometer at the shop will be a job for my navigator, Bill, along the way testing the vent temp. Should be able to get some ambient temps that aren't in the mid 90s in central Pa, I HOPE!
Typically if it 's going to be in the 90s the black 86 usually sits, no need to punish it in the sun if not necessary, and punish me for driving it. When the need arises, like this weekend trip, the A/C need to be available to keep me happy. And all touring cars have good A/C.

Will get back to looking at Superheat again next week. Ordered another temp probe for my Flute so will now be able to read inlet and outlet evap temp.

Order a new Metri-Pack 480 plug and extras female terminals for it. That is the GM connector I used on both the Spal electric fans. The pass side fan had an issue at that connector which i fixed, but need to have a standby waiting in the wings if needed.

Early up, early out the door tomorrow, happy trails.
Bob



Last edited by mmc427ss; 08/27/21 05:31 AM.
#1071827 - 08/27/21 01:51 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Enjoy the trip, and stay cool!


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071848 - 08/29/21 06:43 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Well, how's was the trip and how did the cooling and ac do?

#1071864 - 08/30/21 05:02 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Got back early afternoon Sun from KOTM, just shy of a 600 mile round trip. The cooling system is back to where it was prior to all this carrying on, gauge temp is rock steady no mater 90 degrees, 70+ mph or idling hot. Last night, 12:30 am, actually needed the heater and defrost in UMI's back country parking lot. Hindsight now says I should have popped the hood to watch the compressor cycling in the cold defrost mode (heat and A/C) while it cleared the windshield. But it's not cool to be working on your car in the parking lot full of race car haulers and predominantly Chevy guys.

The coolant level cold has been spot on the line the last couple times checked. How much hot coolant that has been pushed over to the reservoir can be used as a visual measure of engine temp. Generally hot day, hot engine may see 1/4" above the line. When at that last autox and the engine overheated into the 230 range checking level was at 1" above the line, that's when i pulled the plug on the last two runs of that day.

Watching coolant level when cold I've monitored for years on this engine. You see that level change you look for, and fix that leak. A couple years ago suspected pissing out the back corners of the cyl head area, barely noticeable because it only happen under heavy accel periods, and left white dots on the stainless exhaust pipes. Assumed it was head gasket but could't follow a trail back to that source. Coolant level loss you could measure but was so minimal, hardly noticeable if you didn't pay attention to the level but white dots on the exhaust where present. Prior to that changed antifreeze to a Zerex GO-5, old antifreeze aged out. That GO5 antifreeze was the cause of my leaks at the head gaskets. Even with a couple of Bar's leak tablets i chased the source for months. Finally dumped the GO5 and flushed the system and installed Peak Global Lifetime with a tablet, no more white dots on the stainless exhaust. Monitoring coolant level for me is a good troubleshooting tool.

A side from maybe tweaking the temp sensor operating range on the new Cool 125 the cooling system is good. As mentioned i make scrounge up some brass tube to make two heater hose Tee for cold recirc in the engine. The idea sounds to simple, not sure why i didn't think of it 14 years ago when i first put this engine together.

A/C, still not happy. Fri trip was 90% 70 mph, near 90 degrees running on Bi-level, medium, 46 average. Best we could do was 42 on Max blower on high at 70 mph. Today it was much cooler ambient in the AM and we took the 45-55 mph route home through the woods. Bi-level, medium fan getting 46 is very comfortable but should have needed to back off on the full Cold setting but didn't.
Bill, my copilot, who has played with a little A/C in his lifetime, both he and I think the next step is remove a little more 12 from the system and raise the Superheat temp from 10 to 12 and see what the result is. One thing we both noticed as we hung out in the hotel parking lot with the car off was how long and how much water was laying in the parking lot under the evap drain. This is probably an indication the evap is frosting over and reducing efficiency. So nothing to loose by upping the SH.

Pretty sure it's not a question of the evap drain being clogged, was in there years ago and cleaned both drains and the insides of the evap area. The wife was using the car as a daily and her parking space at work was under pine trees. Those short little needles got through the cowl screening, down to the drain holes and eventually became a problem. Even her new 02 SS would clog the drain holes in the door over time with pine needles and would need to clear those drains. Even had to clear the blockage in one of the sunroof corner drains once. By the way her bosses had the parking spots with no needles.

Second temp probe for the Fluke VOM should be here soon, Will try to get an accurate idea on how the evap is performing and hoping to dial that in soon.

For a 600 mile trip didn't do a real gas mileage check. Do know it was 600 and consumed right around 30 gallons of gas. Not terrible for a big cubic inch with 4.11 gears, running A/C the majority of the time. I did tweak the cruise A/F setting a tad leaner before we left but at 72 mph cruise speed was seeing 14.6 A/F average. I shoot for 15-15.1 for those long haul drives but fuel mileage didn't suffer much at 14.6, and cruise control helps, especially with a 6 spd. .
Had to stop for gas on the way home today and pump in some Sunoco 93. OUCH, $4.099. Gotta love PA.
Bob

#1071956 - 09/06/21 06:47 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Wouldn't you know it, took my two grandsons to two car events on Sat. At 7 am and after dark needed the heater, no A/C, windows could actually be down today.
Sat was the Duryea Days show and sat evening was the show downtown, near 700 cars there.
But no real evaluation of the A/C on that day. Will be taking the car to Cecil County Dragway this Sat for the Buicks event to look at GNs and GSXs, also will make a couple passes down the track to see if the new 200 wear tires stick any better than the 6 year old rubber.

As far as the cooling system goes it's dialed in again, working great. Just so i have new parts on hand for the plug on the fan that failed a new plug and extra female terminal are in house.

Relating to the adding a cold coolant recirc to this engine.I found only one place, Australia, to buy a 5/8x3/8x5/8 and 3/4x3/8x3/4 brass barb Tees and they are salty and used in certain applications, it's an odd combo of hoses. Looking at sourcing the brass rod to make them on the lathe also.

Had both temp probes taped and insulated to evap, inlet and outlet, to monitor temps and compare to the PT numbers on the low pressure gauge. Played with charge a little but ran out of time doing the procedure and will start over again this week looking for that optimum SuperHeat number.
Bob

#1071973 - 09/07/21 11:38 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Its still warm here in Tennessee but like you said its decent in the mornings and nights, I really like this time of year due to the cooler weather but I also dislike because old man winter is getting closer and closer. I bet the grandkids have a good time out and about in the monte.

Let's us know how the tires hook on the dragstrip.

#1071980 - 09/08/21 01:10 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Well Bob, Personally, I think you are over thinking the situation with the A/C proper charge. Yes, they teach the superheat theory during training, but in the long run automotive wise, it's much simpler than that. Household HVAC, it's more critical and no I don't do HVAC. At my work, we had to check the A/C system and if the charge was low, we did leak checking on the system, pressure switches were our biggest problem on diesel engines that shake everything attached to it, recover what left, replace the switch, evacuate the system and see how much oil was removed, calibrate the same amount into the oil charge system on the charging station and inject the oil first and then the proper measured amount of refrigerant that is on the system label. JMHO, no real magic there!


Leo Paugh
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#1071984 - 09/08/21 05:16 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Leo you are right, with lots of time to over think things I find I still want to know the how and why of things. And unfortunately don't have one of those fancy machines to service A/C. When the system was all cleaned out, new compressor and parts, 7 oz spread around correctly, a weighed amount of 12 went in. What happened was the scale and I weren't on the same page, and a 1/4 lb to much went in. Rather then evac again, the scale and vac pump went back to their owner prematurely, I decided to play the game with finding optimum performance the hard way. Don't get me wrong, the A/C works very well, just think as us tuners do, try and get the most out of what we have. And as said an education of A/C was in order.

Funny you mention doing the system by the book. When you study the pages in the HELM'S about the system you can easily see that the parameters for a performance check are large, temps out the vent between 38-46, pressures, cycles per minute, good to go if you fall into those parameters. Have several different Helms for several GM vehicles, no specifics, just parameters.

Saturday going to Cecil County for the Buicks event, GNs and GSX cars are cool, will make a couple passes on the car to see if mph hasn't lost a step. Bolted the new 200 wear, RT660 tires back on the car to see if they will actually hook a little better and get sub 2.0 sec 60' time.
One thing I always appreciated was on the 60 mile drive back home after a hot day at the track was having cold A/C after being in the sun all day. Will monitor the vent temps on the way home. Won't be long before A/C will be off for the cold days ahead. That will put a damper of any final tuning of the system.

Have found the necessary brass 1" round stock to make the brass Tees for a bypass feed to the water pump on this engine. No hurry to get that done, just another evening of sitting next to the lathe and whittling them out. Hardest part is boring them, finding the necessary tooling. I made a bleeder Tee for 3/4" hose several years ago, installed that at the highest point in the system, heater core exit. So not a big deal making a 5/8 and 3/4 Tee now.
Bob

#1071987 - 09/08/21 08:03 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Yep, it helps big time to have the machines at your disposal at all times!


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#1072062 - 09/20/21 05:39 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Made the 60 mile trip to Cecil County Dragway last Sat, it was packed, took 1/2 hour just to get through the gates, another 1/2 hour to find a place to pit my friends truck and trailer. Have been to Cecil maybe 10 times and never saw the pits that full. It was a Mandra events so those cars were there but the Buick event drew a large number of Buick cars, many of them A bodies in the form of fast race cars. Close to 50 GNs including, 2 GNX (one with 1500 miles on the odometer), a 1/2 dozen T Types (my favorite), even a 68 Chevelle station wagon with a GN engine swap, and two 89 Pontiac GTA with the turbo Buick factory installed. Of all the 3rd Gen F-bodies those 89 turbo Birds are my favorite 3rd Gen.

Finally they called for T&T after lunch, it's been two years since last making a pass and have no idea how the new Falken RT660 will behave. A 2 second dry burn, stage, and spins at the launch, spins in 2nd, mind you this is granny shifting, then in 3rd gear the car fall on it's face to the lights. What the heck, 14.2 @102, crumbled that time slip up and tossed it in the back seat. Two hours later and a cheeseburger, 2nd pass time, wussy (polite) foot it this time and a 60' of 1.93, 12.92 @112 and the car made a clean pass through the lights. Last pass was in the heat of the day, 3:20, car ran pretty much the identical pass but with a .2 slower 60' so 13.1. another 112.1.

With only three runs not enough passes to really figure out the launch. And I didn't push the engine, and a 10 mph head wind. My friend 69 Camaro ran a 11.9 @112, it's a street car with a drag race setup, 2 tenths slower that day, by the way it has a 327". Typically I'm in the mid 12s with street tires, 114 average on clean passes. For me drag racing is about mph as the measure of how is the car running. Weighing the two passes I'd say it still pull hard in 3rd and 4th and hasn't lost much of a step in the 15 years since putting it together. Just the old man isn't a sharp as he used to be.

About the cooling system and A/C. New fan controller is back to being seamless, rock solid temps. On the way to the drags ran the heater for a while, didn't need A/C in the morning. On the trip home in the late afternoon, low 80s and the sun was hot found I wasn't getting good air flow out the dash vents, Hmmmm. The interior was comfortable running Bi level but not annoyingly cold. A few days later found time to look for a reason for low flow from the vents. Did the usual, check ground path to blower for loss, voltage to blower, all good on the original motor. But while testing, engine off blower running, felt air leaking from seal at the evap exit from the suitcase. Fixed that and big improvement in vent flow. If that foam seal pushes out again I'll put a dab of RTV to hold it in place.

With some time to spare decided to check the heater-A/C vac system. Pulled the vac hose off the vac reservoir and hooked the Mightyvac to the system at the ball. I had done this a month or so ago and could pull and hold a 15" vacuum on the system. This time a zillion pumps and wouldn't hold a vac. Hmmm.Behind the glove box door is access to the valve that controls outside/inside air circ. That valve good, air door functioning and sealing perfect. Above the gas pedal is the valve for dash-floor direction, it also is working and sealing perfectly. The valve for defrost is way up there above the dash-floor valve, didn't have the desire to check that one yet.

I suspected the leaking was in the rotary vac control switch now not seating. Had been moving the selections a lot while testing with the engine off, using MightyVac and couldn't pull a vacuum. Started the engine and instantaneous application of 15" vacuum seated the rotary switch, all selections worked fine. Shut the engine off and waited 15 minutes, pull the hose off the vacuum reservoir and still had lots of vacuum. It's high vacuum that keeps the rotary switch happy, sucking it together to make the seal. So that 35 year old vacuum systems seems to be okay.

While the hood was up pulled the blower motor, checked all the connections, removed and washed the blower wheel which was actually pretty clean, blew the dust out of the motor, armature/brushes well used but still serviceable, four vent holes in the side of the motor allows that. Used the MightyVac to activate the outside/inside air door to check for seal, good. A lot of the evaporator can be seen now, used a shop vac to suck out two or three small pieces of debris laying at the bottom front of the core, the core was still looking good since the last seeing it 15 year ago when the heater core was replaced. Nothing laying in drain area under the blower.

Reinstalled the blower motor, and feel things are as good as they can get for now. Maybe a new motor may spin a little faster on HI, maybe.
Will do more pressure and temp testing on the A/C system now that ambients temps are much cooler, 70s , in the coming week.

In process of modifying the cylinder block coolant bypass system. Currently with the Dart block all bypass coolant comes through the thermostat when the engine is cold and heater is closed. With three 3/16" holes in the thermostat to supply bypass water to the pump to much flow is going to the rad and engine wamup is slowed a lot. Making an H pipe that will be installed between the heater hoses so when the heater valve is closed coolant will flow out the intake and directly into the water pump inlet side. Was going to machine brass and make the H but have now changed to making it out of stainless tubing. A 12" piece of 3/4", 5/8" and 1/2" all .065" wall was ordered tonight. Using stainless will allow the H to be TIG welded, the brass would need to be soldered, didn't trust the possible stress on a solder joint with minimal contact area. A bead roller to do two 3/4" and two 5/8" beads on the tubing will need to be made. The guy that will TIG the H together said he can TIG the beads on the tubing but I will try to roll them on first. .065" stainless tubing will be very difficult to bead with a homemade bead roller but I've got lots of tubing to play with.

Registered for another Sat, Oct 2, of 16 autox runs today. It was three months ago at the last autox that the overheating reared it's ugly head. It will be much cooler that day, and i believe the overheating problem has been solved. Also planing another trip to the drag to make passes on Oct 15 or 16. These will be the last events of the year as the doldrums of the Winter season set in.
Bob

#1072283 - 10/21/21 05:26 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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Guess a followup is in order.

Ran that autox on Oct 2, a fun, tiring day, learned a lot, The cooling system worked flawlessly so getting that back to seamless was accomplished. Temps were in the low 80s that day so not a good test of the A/C in the late afternoon return ride home. Being it's getting colder here playing with the A/C system to get max performance on a 90s day ain't going to happen till late Spring.
Happy with it now but made a few observations to address.

The original blower motor and fan were pulled and the fan blades cleaned. Voltage and ground circuits verified good. This done in hopefully increase vent air flow. All the doors in the suitcase were check for function and seal and are fine. The door and roof seals are all new. The Astro Ventilation vents in the door jamb by the strike were removed and cleaned and checked for function.
What is noticed is how much the center vent air flow is reduced when the windows are up and sealed. That sealed compartment should cause the blower motor to have an increased load on it, maybe slow down.
Examining the original blower motor a visual said the commutator looked serviceable, but being a dc motor with brushes isn't always a good indicator. Cleaning, polishing the armature wasn't a consideration. So on the shopping list is to see if a new motor can be sourced that may have been made on this continent. They are reasonably cheap, possibly a Delco replacement can be had. But more than likely everyone selling a motor sells the same motor, just a different colored box.

So A/C project is put to bed for the Winter. Have already had to use the heater several times.

Regarding the H pipe for the cooling system bypass, DONE, installed and being evaluated. The Dart engine blocks don't have that 3/8" hole in the block at the right side of the water pump. On an OEM SBC that 3/8" hole is present and supplies coolant to the inlet side of the pump when the thermostat is closed and the heater valve is closed. That the 3/8" hole allows coolant to circulate within the heads and block during engine warm up.
With no 3/8" hole in the Dart block for years I've run a thermostat with three 3/16" holes and a 1/4" OD pipe from the rear of the intake which is close to equals the flow of that 3/8" hole used for stock bypass coolant feed.
The downside to all those holes in the thermostat is engine warm up is slowed because of all the bypass coolant is now coming from the radiator unless the heater valve is open. At that time you still have a lot of cold coolant from the rad feeding the water pump.
Now the thermostat only has a small 1/8" hole drilled in it to vent the chamber under the thermostat, a normal SBC mod. The 1/4" tube plumbing is still bringing coolant from the back of the left and right cyl heads to thermostat housing. The new H pipe is installed between the 5/8"and 3/4" heater hoses and has a 1/2" crossover pipe (3/8" ID) and is now supplying bypass coolant to the pump inlet when the thermostat is closed and the heater valve is closed. And is supplying coolant even when the engine is hot.

Have had the car out 4 times for long hard runs "around the block" and out on the highway at 60 mph and system seems to maintain the same temp once warmed up. Looks like a win-win so far. For 15 years dealt with that problem with this Dart block. Just surprises me i didn't think of doing the H pipe prior.

When the system was drained to install the H pipe and all new heater hoses it was empty with the exception of the heater core and of course the engine blocks low points. The new vacuum coolant fill tool is the cat's meow. You draw down a vacuum in the cooling system. Let it sit with 25" of vacuum on the gauge for 15 minutes or so and that lets you know you don't have a leak somewhere. Connect the filler hose to your bucket of antifreeze and suck in the coolant.
Filling the Dart block/Stewart water pump combo and getting trapped air out of the pump have been a problem from day one, 15 years ago. Once the air is out the combo works great. This vac fill tool is so easy to use and solved that problem, just plug and play, done.

Will stick a new blower fan motor in while you can still buy a good one. Cooling system and A/C and also the new electric fan controller all seem to be back up and running fine now. Soon time to move onto the next new project.
Bob

#1072284 - 10/22/21 01:18 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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86ttop Offline
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Bob, When I replaced my heater core in my 86, I replaced the blower motor and the air flow was amazing afterwards. It's an old blower motor now anyway!!


Leo Paugh
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POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs
#1072286 - 10/22/21 05:29 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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Leo i went ahead and just ordered a new Delco from Rock, it was the best deal i found. There seems to be a lot of our blower motor/wheel, 15-80213, available in Delco right now, Ebay is flooded with them. Supposedly made in Canada, I hope.

When i did the door window motors a little while back, used Delco there too. When you dissect the old motors the contamination of the commutator by the gearbox grease was a major reason for the old motor's slower speed. On the blower motor the bushing sits above the brushes with a oiled wick felt.

Will run both the new and old motors on the bench before installing the new one. Hoping the new motor spins faster.
Bob

#1072288 - 10/23/21 01:15 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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86ttop Offline
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thumbs


Leo Paugh
It's not an attitude, it's just the way I am.
POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs
#1072314 - 10/27/21 06:36 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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Another update of the A/C- heater progress.

The new Delco, 15-80213 ordered last Thurs showed up on Sat morning, and Made in Canada. With both the new and old original on the bench ran both at 12vdc, the new blower was notably a little faster spinning. Although slightly weighing less than original the quality was very good, appears near identical and had no regrets installing it.

Installed it Sat afternoon, no testing done. Sun morning there was supposed to be a cars and coffee at 9 am, so we headed out, low 50s and needed the heater to keep the toes warm. This was also testing for the new water pump bypass circuit now being feed by the H pipe between the heater hoses. Needed to see what if any effect that H would have on the cabin heat. Can say no noticeable change, tons of heat now with a new blower. If fact it worked so good turned the fan to low and still making tons of heat. So started to reduce the heat via the control, then reduced some more, then some more and now on COLD the still cranking heat. Hmmmmm.

Monday dropped the glove box out of the way and found the pivot pin on the plastic blend lever was broken. At first didn't notice the cause of the pin breaking, but it was because the attachment to the housing of the cable had broke, the angle of the cable changed putting extreme side pressure on the lever pin,snapped it off.
Both the lever and cable need replaced now. Mike's Monte has them on their way already.
https://www.mikesmontes.com/Air-Distribution-Door-Control-Lever_p_2703.html

https://www.mikesmontes.com/AC-Heater-Control-Cable-Free-Shipping_p_3124.html

Couple notes about the insanely hard to remove broken pin located in a place you can't even see.
First remove the glove box entirely, 5 screws and out of the way, also the trunk release and glove box light bulb. You'll be spending some uncomfortable time doing surgery through that hole in the dash. Because the broken pin is a T pin it goes into a hole that is slotted for the T. A new lever/Tpin is aligned to the slots in the housing and pushed down into the hole. When rotated the T doesn't allow the pin to rise out of the hole.

When the pin breaks the tee may be "locked" into the housing and will need to be realigned to remove the broken pin. After trying numerous mini pliers, hemostats, tweezers, frustrated, walked away for the night. The brain storm hit me the next day, a 2" alligator clip with crimp end bent at a 90.degree. The pin is about 1/4" OD, with one hand get the clip on the short stub sticking up, trial and error. Then with two fingers squeeze jaws enough to have a good bite with the teeth of the clip. Now pull up gentle on the clip and the pin will rise a little. Remove the clip and choke down lower on the pin. Now firmly squeeze the jaws/teeth of the clip into the plastic pin. Carefully, slowly turn the pin with the clip, aligning the T to the slot. With a 1" telescoping mirror i could see into the slots to align. Once aligned the broken pin came right out. The alligator clip was god send, thanks.

One end of the lever is pulled and pushed by the cable from the dash controller, it's attached to a plastic stud on the plastic lever. Sometimes that stud will break of, mine was good. The other end of the lever connected to a threaded steel rod which is used to move the damper. On the lever a connector insert is used to set the closed position of the damper. The threads on the rod snap into that insert. Before disconnection that rod from the old lever mark the position of the rod to the insert with a marker to make new reinstall/adjustment easier.
There is only that adjustment for the damper, no adjustment on the cable side of the lever.

Have read that you can just push that T pin down into the housing instead of removing it. There are a few very good videos of a complete tear down and rebuild of the entire A/C suitcase, on a workbench, very good info there. But no where have I seen any info on pulling the broken pin. But I did see what appears to be the pin hole is blind, and a molded in pocket for the pin won't allow pushing the pin down and out.
By the way cud-dos to the 4th gen 442 guy who did a three part series on the suitcase rebuild.
https://www.youtube.com/watch?v=yFZ9q9lLPy4

As mentioned the cable from the controller to the lever needs replaced, the probable cause of the lever pin failure. Controller removal is necessary and already hanging out of the dash but will get into sooner than later. Still evaluating what needs to be done to R&R that.

Just happy that PITA pin is out.
Bob

#1072398 - 11/04/21 06:27 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Need to put this post to bed.
New lever and cable were sourced at Mike's Monte, thanks Mike for the quick shipping.

In order to disconnect/change the heater cable the controller needs to be flipped over. With the controller out of the dash both electrical connectors and the cluster of three hose on the left rear corner are removed. Leaving only the cluster of vac hoses attached to it, the controller was cleaned and a little lithium grease applied sparingly to necessary moving parts. That cluster of vac hoses are held on by push nuts on two plastic studs. I chose not to remove those nuts fearing stud breakage, old plastic. Just insured when the controller would be slid back into the dash all those 6 or so hoses are fully seated.
A push nut is used to hold the new cable loop to the pin on the cold control plastic pin. Be careful.
There is a push nut used on both ends of the cable, i reused both the old push nuts

Installing the lever was a little tricky, a light coat of lithium on the pivot pin and it took some effort to push it into the heater housing pivot hole. New cable was attached to the controller, controller installed in the dash, cable to lever end installed and cable support clip then pushed into it's hole in the housing.
The rod to the blend door itself is the adjustment, it has threads on the lever end and snaps into the clip to lock the threads to the white adjust pin on the lever. You adjust to the full closed position of the blend door at that point. Using a magic marker on the threads was done to mark the original position before disassemble.
Pulled the blend tight against it's seals in the heater, putting the cold control at full cold and then connecting the blend door rod to the lever was done. A check showed at full cold setting the door was fully closed. I'm adjusted just slightly tighter than the magic marker on the threads. Sliding the cold control requires just a little more effort than the past 30 years but I'm OK with that.

I tried to heat and bend the new plastic sheath of the cable but found it didn't like to be heated and quickly abandoned that idea. The original now broken cable sheathing fared very well with heating. The run of that short cable should have two slight bends in it to be relaxed when installed. You only want to bend the sheathing, not the steel cable inside. Not wanting to destroy the sheathing with heat the cable was installed once I straighten the steel cable from shipping.
So blend door/heater unexpected issues are now good as new.

With the center of the dash apart the Delco CD with EQ also removed from the dash. It was originally used in the early 90s Buick Roadmaster, Typhoon and Syclone and very limited production and a 1 1/2 DIN. I wanted stock appearing, CD, and EQ for the 86, it looks totally factory. For the past couple years it had an problem with not seeing, reading certain CDs.

It went on the bench for surgery, split the unit open and was about to remove 6 or 7 thirty year old ribbon cables from the CD drive to be able to get to the laser. STOP!
I've played with ribbon cables many times before but none this fragile, it still plays most CDs, why would i want to end up with the operation a failure and have a non working CD player. Reassembled it and tested before it slid back into it's opening in the dash. Ran my CD cleaner disc several times and satisfied that it will play 50% of the discs I have.
I did learn something about that unit. With all the work done under the dash dealing with that PITA broken lever pin, the cable, the controller, the Delco the interior lights were on, draining the battery. When I finally had the center of the dash all back together and now to test the Delco turned on but wouldn't do anything but show the 20% volume up and one preset station. The balance, fader, CD, clock, volume, nothing worked. WHAT, went home after that. Laying in bed, the brain light turned on, check the battery voltage.
Next morning meter said 12.3, a check of the Delco and everything OK. Turned on the headlights and fairly quickly it dropped to 10.7, Delco stupid again.
So the Delco doesn't like low voltage, didn't know that.
The battery charger ran overnight at 4 amps putting some juice back into the battery. Everything all well and good now.

This kinda finishes up this long process of freshening up a 35 year old A/C/heat system and cooling system. The A/C system is as stock as stock can be and on a R12 diet.
Lots of new parts in both the A/C side and heat systems, better fan control, new coolant bypass system and now the vac coolant filler tool.
Being the pumpkin had frost on it this morning revisiting the A/C charge and performance of the system will need to wait till the sun points back up North. I drive this car for fun 12 months a year if the weather permits. When it's cold out sometimes just to move the oil around in the engine or charge the battery a little.

Other Winter projects on the back burners now.
Bob

#1072406 - 11/04/21 11:56 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob, you mentioned the 1.5 din delco a while back, it piqued my interest so I headed over to ebay. From time to time they are there but if in really good shape in the neighborhood of $300+ dollars. Im sure if a person wanted they could find it cheaper but I was wanting a pristine if I was going to buy one.

What is your planned projects for the winter?

#1072407 - 11/05/21 02:34 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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You need to be careful about year and model the 1 1/2 DIN Delco players come from. It was 13 years ago I installed the Delco in the dash. Because of differences in the size (width and depth) of the various 1 1/2 DIN GM head units the 3rd and 4th Gen Camaro/F-body was the unit everyone was swapping in at the time, a plug and play. They will slide right into the Monte dash. At that time when you bought a unit a wiring adapter was made that would convert the single G-body plug to a three plugs to go into the back of the new unit.
Also the display colors for different GM makes was an issue. The Pontiac units, Firebird in particular, is orangeish, doesn't look good in the dash of a Monte.

Also at some time all the CD players went through a change, maybe around 1994-95, to a different transport. My 1992 unit has the old transport and is impossible to find parts for today. I also believe about that time was when Delco/Delphi production moved manufacturing to Mexico.

Also you will see Bose and Monsoon F-body unit for sale. I was told to avoid them because they were purposely build systems, speakers, amps and crossovers all needed to sound good.

That Roadmaster unit in my car was bought from Ebay as refurbed for 300 bucks back then. I watched for months before the unit showed up on ebay, they were that scarce.
Bob

#1072408 - 11/05/21 02:39 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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Bob, will probably never do it but I've always just looked for the early model 90s roadmaster radio on ebay.

Last edited by 88ssBrent; 11/05/21 03:57 AM.
#1072415 - 11/06/21 02:09 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Offline
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One of the reasons they are scare is the GN boys grabbed as lot of them up so they could use a CD and have the correct display color for their Buick. Cassette was what came in the late 80s cars, also the EQ cassette was the top option in the 87-88 GM vehicles. 1989 may have been the first year for a CD player option at GM.
Bob

#1072556 - 11/23/21 09:52 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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tom demarco Offline
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GMHVACRESTORATION.COM great site for dash console repair

Last edited by tom demarco; 11/23/21 09:53 PM. Reason: spelling
#1072583 - 11/28/21 02:42 PM Re: Why now, A/C R&R [Re: mmc427ss]  
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GMHVACCONSOLERESTORATION.COM he has everything

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