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#1071310 - 07/10/21 06:03 AM Why now, A/C R&R  
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mmc427ss Online content
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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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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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Murphy's Law, that's why now.!!


Leo Paugh
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POW*MIA
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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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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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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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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
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POW*MIA
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#1071363 - 07/19/21 03:13 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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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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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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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]  
Joined: Jan 2000
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mmc427ss Online content
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mmc427ss  Online Content
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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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Leo Paugh
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POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs
#1071435 - 07/25/21 05:39 AM Re: Why now, A/C R&R [Re: mmc427ss]  
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mmc427ss Online content
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mmc427ss  Online Content
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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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mmc427ss Online content
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mmc427ss  Online Content
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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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SSLance Offline
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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]  
Joined: Jan 2000
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mmc427ss Online content
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mmc427ss  Online Content
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Pottstown, Pa
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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88ssBrent Offline
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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?

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