Back in the fall I started working on the AC system in my 1987 Corvette and brought the car to a friend who works at a shop who performed the retrofitting to convert the car to R134a. The dryer was replaced and all the new fittings were put on the car at the time, as well as emptying the system and pulling a vacuum. Long story short, the AC system was ready for the new oil and refrigerant. Once I put the new stuff in, the compressor started to kick on but the clutch started smoking and nothing happened. My questions is whether or not I need to replace the compressor or just the clutch. I'm hoping it will just be the clutch because I do not have the tools to empty the system and pull a vacuum again. If anyone has gone through the same scenario or has some information on where to go from here it would be greatly appreciated. And if I do need replacement parts, if anyone has any for sale I would be willing to take a look and possibly work out a deal. Thanks!

 

Did you install the correct amount of oil and refrigerant? Overcharging will lock up the compressor because you can't compress a liquid. That will make the clutch or belt slip.

 

I believe I put 6oz of oil in before I put any freon in the system. That's what was originally called for with r12. The system still has all the oil and the small amount of freon in there. I never got to fill it up because it started to smoke while running the AC.

 

When I did my '87 I drained the old mineral oil from the compressor and flushed the system before adding the ester oil and R134a. As RWD mentioned, too much oil can lock it up. It's unusual for the clutch to slip like that unless the compressor won't turn.

 

so you charged it a little, then went to turn on the car with the ac on blast to charge further? Fyi you're supposed to cycle power to the ac off and on a few times at first to push some of the oil down the line. Not sure if that's what caused your failure though. When was the last time you ran the ac compressor before swapping to r134a? Sounds like your ac unit is seized up and when the clutch engaged it fried the clutch. You can try replacing the clutch and maybe that will work, I dont know.

I followed this guys guide on my 87 and it worked very well.
I also recommend charging w/ one can of dyed r134 do you can find any leaks if there are any.

 

I'll try cycling it and see if that helps, but if I had to guess from what happened before, the clutch is probably fried. I watched this video back when my AC wasn't working and it gave me some useful information on the AC system in the Corvette. I bought the car in July with the "AC working, not blowing cold"...really bit the bullet on that one with those 90 degree days in the midwest. As for the leaks, my buddy who helped me empty the system pulled a vacuum on it and tested for leaks, so no issue there. I will probably just pull the compressor and see if I can free it up. Anyone have any tips on pulling the compressor? I don't know much about AC systems...this will be a learning experience!

 

Can you turn the compressor by hand? You can also engage the clutch by providing +12 to it with the engine off to see if it's totally toasted. If you open the system again you will need a new receiver/dryer and have it vacuumed again. You should also change the seals to the green ones and replace the orifice tube if they were't done already.

 

I am able to turn the clutch a small amount. It definitely has resistance and it will only turn a small amount in each direction. This was true before I put the oil in the system. I though oil may free it up a little, at least that is what my buddy told me could happen.

 

When I did my r134 swap I bought a brand new ac compressor and I could barely turn it by hand. I mean almost not at all.

i once had a jeep where the ac compressor seized. I was driving down the road and all of a sudden everything smelt like burning plastic and my cold ac went warm. Checked under the hood and the ac compressor had flung melted plastic all over the engine compartment. I bring that up because I could still try and run the ac with the clutch being toast, I don't think you run any risks in trying. You may be in for a replacement - not the end of the world.


To remove the ac compressor you need to remove pressure from the system. You're supposed to have the r134 in there recovered. Then loosen the belt tensioner and pull the belt off. Loosen the bolt holding the suction and discharge hoses on the compressor. Loosen two bolts on the back of the compressor, one runs into the valve cover so have fun with that. One more bolt on the bottom of the front, it's a torx bolt. You have to align a flat spot on your compressor pulley on the bottom to remove this bolt all the way. Make sure to clean it with a pick before attempting to remove. If you strip this bolt you've entered a world of pain.

I followed Kevin's video that I posted above almost to the tee, it's super helpful. The guy is so nice I asked a question on his video and he gave me his damn phone number if I needed more help.

 

I would ask why was it broken in the first place. I replaced my 1985 with the ecklers kit. It comes with a compressor, dryer, orifice screen(it is different for r134). and I put all new green seals. I put my 6oz of ester oil
in with 1/3rd in the line before the compressor for 1st start up. put the rest in the lines and evaperator/condensor area. You did it right but mine did not smoke then look at gauges and get around 45/200
pressure readings at 80 -90 degrees outside when the compressor kicks in. I used 40oz of freon. I would say just replace the compressor unit as a whole, and change flush the tubes, I even flushed the condensor with ac cleaner and ran the hose to flush it out. let it all dry completely then fill again after the vacuum because you cannot fill it otherwise.Good Luck!

 

So the capacity is 6 oz and you left the old oil in it and put new oil? Isn't that kinda doubling it? Also, will the oils mix?

 

theres some type of shortcut that's been going around where all you do is add mineral oil or esther oil, change the fittings, and then charge with r134. I saw it on a miata forum. The problem with that is it ignores the hydraulics involved in a working ac system. The operating pressures on r12 systems are different on r134 systems.

 

The old mineral oil needs to be drained, it will not mix with the new.

The old mineral oil will typically migrate to the condenser and reduce efficiency of system.

 

Shortcut? Isn't that the longest distance and the most convoluted route between 2 points?

Last time I did it, I changed the hoses to the new onea, flushed out all the lines, change receiver dryer, dumped the screwed up compressor. If I reused the compressor, I would drain the oil, flush new oil into it and turn and turn it, let it drain overnight and refill with the right stuff