Project C4, 85 Corvette

[Steve85]

TL;DR - It worked, then it didn't, and now it does again.

After having the AC work great in the driveway for 3 days I decided to take it out a couple weeks ago and AC stopped working before I even go to the bottom of the driveway. Not cool.

The difference was disconnecting the trickle charger, it was providing just enough juice to make up the difference from a low voltage problem to keep the compressor clutch engaged. After driving it a few miles to get gas it also gave me a chance to double check for leaks and it seems every internal compressor o-ring gave up. Oil was on the clutch shaft, seeping out between the body and shell, and anywhere else it had an o-ring. Not a surprise I guess, old, old compressor. (Very odd that it did wait for me to drive it though, was clean in the driveway...)

 

Ordered and installed a new compressor from Rock Auto. As is often the case, my car had a compressor that was only used for a couple years so of course even the new ones are a slightly different style. The main difference is the how the suction/high pressure manifold mounts to the compressor but I had enough leeway in the hoses that everything fit.

I had to go through the whole vac and recharge process again and so far so good. I also had to trim out some of the under hood bracing since the compressor sits a little higher than stock. Compressor bracket and upper hose were hitting the hood occasionally and it caused a few leaks. Once cleared and tightened up, no more hitting and no more leaks. (probably need to top off some refrigerant though)

I mentioned above needing to wire the fan and that is crucial too. In all my freon charging and testing, I had my shop fan blowing in the front. When I started the car without it, the AC would not cool until the engine warmed up and the main cooling fan came on pulling air through the condenser. This was originally controlled by the ECM that gets an "AC on" signal through a pressure switch and runs the cooling fan. Since I have two fans, the main cooling fan and a pusher fan in front of the radiator and condenser, I wired the pusher to run as long as 1) AC was selected in the control head and 2) the switch that spoke to the ECM now just directly grounds the pusher fan relay. 

Today was a great test day with full sun and temps in the 90s. Had a bit of a hiccup yet with the low voltage issue at start-up but I cruised for about 30 minutes in mixed conditions, some stop lights and cruising anywhere from 35 to 65 and the vent temp was a solid 42 degrees! Even with 42 degrees at the vent, with full sun and no tint, it had to work hard to maintain comfortable temps in the car. 

I need to clean up some wiring, figure out this low voltage thing, top off the refrigerant and I should be good to go.

I think next will be redoing the interior which is really just a few pieces of carpet and some new seat covers. Not doing red again (at least not carpet), the sun wrecked it in no time, been reading that red is the worst for that.