Auto Air Conditioning & Heater Repair: 1993 toyota corolla ac unit, r 134a, toyota corolla

Question
I have a 1993 toyota corolla le 1.8l afe.  I did a motor replacement two years ago and felt because we haven't had real hot summers I didn't need the a/c.  I hooked up the compressor to the motor when I had it out still so it wouldn't be a pain later when the motor was in hooked up all the lines to the pump etc just never filled it up w/ refrigerant/oil etc.  The ac hasn't been turned on in two years but the car has been driven. Now its real hot here so i made the r-134a conversion kit by interynamics and got everything goin. My ac is FREEZING NOW!!! however sometimes the clutch turns and sometimes it gets snagged on something and makes this terrible screeching sound. could this be the ac clutch or the compressor?

Answer
Tim,
I believe it will lead back to your compressor. The reason I say this is...
As soon as you opened the lines in the system 2 years ago, it began drawing in moisture from the humidity in the air. I don't have to tell you that moisture eventually takes a toll on metal objects. If you didn't pull the system into a vaccuum after you reconnected everything... the moisture remained in there and just went to work.

What I am visualizing is happening is... your compressor turns with the clutch engaged. It hits the rough point from the corrosion that might have built up in the system, that "seizes" your compressor. But with your clutch engaged the belt is still trying to turn it. With that much drag on it, your belt is more or less scraping over the pulley until it breaks free and begins turning again. The belt scraping is the screeching sound I believe you are hearing. Kinda like a loose belt... but in reverse.

When you charged the system back up, did you make certain to add the appropriate amount of oil to the compressor? If not, this may be a contributing factor to the problem. Not may be... IS.

I anticipate you changing your compressor sometime in the near future. But I would also recommend you take it to a reputable shop to have them diagnose the problem also. I can only guess and visualize through this computer monitor. Hope you understand.

I hope I was of a little help. Thank you for the question and if I can do anything further now or in the future, do not hesitate to ask. If you found this response at all helpful, please remember to rate this answer.