Noisy A/C

[Squire Edgar]

I had my engine rebuilt and everything went great but noticed when engine is running that my compressor is now noisy. In the 23 years I have owned my car I have never had the A/C working, but the compressor was always very quiet. Could it be that what freon was inside escaped system when it was pulled off engine and now it's dry and noisy? It's the original R12 setup. I was planning longterm to change to 134A. Just not right away. Is there something I can do in the mean time?

[Dakota]

Can you tell if the a/c clutch is engaged or not?  When the a/c system is not active, the a/c pulley will turn but the compressor won't.  The noise might be coming from the compressor that is rotating now but wasn't before the rebuild.  On mine (70 Challenger with a 340 and stock RV-2 compressor), there's  a single blue wire with a connector within about 6 inches of the compressor pulley that energizes the a/c clutch.  A simple test would be to disconnect the blue wire and see if the noise problem continues. 

[Squire Edgar]

Thanks, I will check tomorrow.

[Rich G.]

The compressor shouldn't run if it's empty. There is a low pressure switch on the drier.