Hi everyone it's me with another problem I know nothing about. My Vette just started blowing hot air, didn't hear any noise or anything just one day there it is. I have the dash apart to find the A/C clutch relay and the fuse panel at the passenger side open. My clutch won't engage for openers and when I checked the relay with 12V test light I got no power to it. I thought maybe a fuse but can't find the problem. Any suggestions will be a great help. P. S. I live in Phx. Az. and it will be 116 in a couple days and it's not going to be a cool summer. Thanks in advance

 

Are you sure that the clutch isn't engaging? If the rubber on the clutch breaks down and let's go, the clutch will engage, but the compressor won't spin.

The other thing. If the Freon is low, the clutch won't engage.

 

Thank you JMelton I will look at those those things right away, thank you

 

Well after closer inspection you were right it was the rubber on the compressor clutch. I'm wondering if I can replace the hub without opening the system. Thanks for your help JMelton

 

The complete clutch assemby can be replaced by removing
a 10mm bolt on the nose of the compressor shaft which
is torqued to 10 ft. lbs so it's easy to break loose. Removing
the serpentine belt and a snap ring will allow
the pulley to be pulled off and removing a 2nd snap ring will
allow the clutch coil to pull off.

The clutch pressure plate is bolted to the compressor shaft.
With your hand (engine off) you should be able to spin the
clutch plate with some resistance. If it's hard to spin the
compressor is frozen or going bad. If it spins ok fix the clutch
and monitor the system pressures.

Its pretty common if the compressor is siezed or has a very
high resistance the serpentine belt squeals or melts. The
question is what caused the rubber on the clutch pressure
plate to get damaged? Could be age, heat or was it was
caused by a problem else where.

Here's a video that shows removal of the clutch plate
and pulley. I'm pretty sure the clutch is only sold as an
assembly.

 

Not sure about yours, but on my 96, I was able to replace only the hub plate part of the clutch without removing the belt, or breaking any lines. I found a local Autozone that had just the bad piece.

 

I ordered the hub so we'll see, if it ends up needing a compressor I think I'll switch to R134a. I read somewhere that on a 90 C-4 if you switch to R134a you should put in a bigger condenser, not sure about what to do if it comes to that. thanks for the help

 

I can't speak to the condenser change, but if you do end up converting to 134a, replace the Oriface Tube with a variable tube.

Make sure you check the Chevy Service Bulletins too. There is one that talks about 134a conversions, and it gives P/N's of compressors that have to be replaced.

 

Thank you I'll check that for that variable oriface tube.

 

Great thread!! Lots of info!!

 

Well, I got the hub yesterday and installed it this morning and guess what? that baby blows, BLOWS COLD ! Yesterday the temp was 119 degrees and it will be hot as heck all summer. With fingers crossed we'll see if it lasts. Thanks again to you Corvette folks for bailing me out of another Jam and giving lots of great info.

 

I have a 1990 and recently the very cold R12 AC simply quit blowing cold air. Got a low freon code. Decided not to screw around with it, took it to a local shop where they replaced the fittings, the receiver-dehydrator (accumulator) and refilled the system with R134a. The first pull down leaked, they fixed that, and then the compressor would not engage. Jumping the switch revealed a very noisy compressor, with a repair estimate of over $1100.00 to replace the compressor. Had to be somewhere, so paid 369.00 for their day long effort, accumulator, etc. and left.

Recalled the error codes, and figured the system might need to be reset before it would allow the compressor to cycle. Sure enough, simply disconnecting the battery, waiting a few moments and reconnecting it produced a working, cold blowing AC system. The noisy compressor quickly quieted down, and even on very hot days, my AC is cold.

Interestingly enough, only the fittings and the receiver dehydrator accumulator were replaced. The system was evacuated of R12, and I'm told all the oil was also evacuated and replaced with PAG (if I have that right). Nothing was pulled apart but the accumulator hose connections. No orifice tube. No physically removing and draining the compressor. No new O rings.

Maybe the system will leak. Maybe it will stop cooling. Who knows. But it's been several weeks of very hot weather, with a clear roof to boot, and it's all working fine, for a total cost of $369.00

I wasn't aware the oil could be evacuated and replaced by vacuuming the system, but it did seem to work. The compressor is quiet, the air is cold.

And I avoided the cost of a new and unnecessary compressor by remembering the error codes might have to be cleared before the modified-now 134a system could function.

Hope this helps someone else here...

 

Hey Red 1990 VT that's some good advise and glad you only paid $369 . I don't know if they can remove all the r12 oil by evacuating the system, I heard they had to flush the system and blow it out with compressed air, maybe that's what they did at the accumulator. Glad to hear it's working good and cold for you. I got away with around a $ 23.00 repair and it's been a week in around 110 degree heat and so far so good. I learn so much on Corvette forum

 

None of the oil comes out - in fact, you add the oil before you evacuate.

Replacing the Accumulator gets rid of some - maybe a 1/3. Draining and flushing the compressor and then refilling it should get rid of another 1/3. The last couple of ounces are spread out in the lines, Evaporator and Condenser. Flushing the Condenser is pretty much impossible, so it's easier to replace it.

 

Good info thanks