This job is not as hard as it looks. I think most people can change the evaporater and heater core. It's mostly unbolt the top of the AC box, pull the cores out and put new ones in. My AC has been disconnected (no freon). So if you are changing your AC core and you still have freon in the system then you need to go and have the freon taken out. It would be a little easier if you have the hood off but sometimes they are a pain to get lined up right after taking it off. I used a 7mm, 10mm and 1/4" sockets for just about everything. There might be different sizes but that is what is on mine.
First thing to do is turn the key on just to move your wipers. I moved them up and out of the way. Unbolt the black trim piece at the bottom of you windsheild. And unbolt the windshield washers. Slide the black trim up just enough to get it out of the way.
Next thing is to unplug the 4 electrical connections on the AC box. Unbolt the plastic screen and pull it off the top of the AC box. Next is just unbolt all of the bolts you see on top of the ac box and the bolts that go into the firewall.
There are 2 bolts inside the box where the air comes in. Look down in the box where you took the screen out and you will see them. After all the bolts were out a used a razor knife to cut along the top of the box. Mine was sealed to the firewall. Before you can get the top of the AC box off you need to take the 2 brackets off on the firewall that hold the black trim. I think those bolts were 11 mm.
I took a scewdriver and pryed the box open easy so I didn't break anything. After it's loose just wiggle it around until it comes off. Here is the top of the box off the car.
The AC core just lifts up and out. Since I had the AC box top off I figured I might as well put a new heater core in. Unbolt the ground on the heater core and take the 2 hoses off. Then the heater core just lifts right out. You could spill a little antifreeze or water, so be carewful. There was a bracket on top of mine where the ground went and it held the core in place. It slips on the core itself. Look how it goes on so you can put it back on the new one. I should have got a pic of the bracket but didn't think about it. Make sure you take the foam piece of the old core and put in on the new one ( it goes around the metal pipes where they come out of the box). Before you put the cores back in clean out the box. Vacuum or clean it out by hand. Make sure the hole in the bottom of box is clear so the water (condensation) has a place to go.
Just set the new heater core in, bolt the ground and bracket together and hook the 2 hoses back on. The new AC core should come with sealing strips. If they did put them on (look at your old core). Then set it down in the AC box. Make sure you put the foam around the pipes the same way they came out.
I put some sealer around the top edge of the box before I put the cover back on. Set the cover down in place and start bolting it back together. I had a little bit of the sealer ooze out after I tightened down the cover. I just got a rag and wiped it clean. The rest of the way is just putting everything else back together (plug in wiring harness, washer squirters, black windshield trim etc).
I have to wait until I get the rest of my parts to get the AC going (compressor, drier, condensor etc). I figured this was the hard part. Make sure you start your car, warm it up to tempature and check the heater. If you lost some antifreeze fill it back up. If you are getting the AC going bolt everything else back together (lines, drier etc) and get the freon put back in. There are filters going in the line to the AC core. So if you are getting the freon put back in you need to change it.
Am sure some people can add to this and I might remeber something else. If there are any suggestions please do so.