Today I noticed a grinding noise while my car was idling. It sounded like a dry bearing. The sound got worse after the ac pump cycled on and off. Then it would get a little better until the pump cyled again. It didn't make noise while the pump was going. I also noticed that the compressor was still spinning (very slowly) when it was not engaged. Is that normal?
While driving, I could hear the pump kick in a few times. It sounded bad. Like the clutch was slipping. Didn't sound like a belt.
Has anyone else had problems with their ac pump/clutch? Any ideas on isolating the problem? I don't want to replace anything more than absolutely necessary. The clutch alone is over $200 :/

 

Could be the belt tensioner bearing. It's cheap to just replace a bearing (about $15 from NAPA).

 

It wasn't the bearing. I replaced that today. There is now grease coming from the ac clutch hub, and the pump isn't working. Im hoping its just the clutch.