1997 Mirage A/C Compressor
 

I've got a 1997 Mirage 1.8l distributor-less. There is a noise coming when running and noise subsides when /C or defrost is turned on. My mechanic thinks it could be the A/C clutch. From what I'm seeing it is all one piece...compressor and clutch. Any thoughts. I'm thinking $500 repair.