Put Belt back on.
Start engine & turn A/C On.
Put tip of long Screwdriver to body of compressor, & handle to an ear; if noise becomes louder when clutch engages, either shaft bearing and/or clutch is fubarbed.

And listen[using this technique] for excess noise at each accessory, including tensioner pully, to definitly identify problem component.

NOTE: Use caution, while poking around with Screwdriver, keep shaft AWAY from Belt with engine running !

 

If you enjoy doing your own diagnosis, get this tool:
www.lislecorp.com/tool_detail.cfm?detail=958

 

Thank you again, Larry, for your informative reply... I have pretty much determined the noise was coming from the AC compressor (I sure wish it was the alternator... ). When I turned on the AC, it would cut in and out. It made the noise again this morning when I started the car, but once I drove for a while it went away.

I am going to elect to ignore it for now, however if it is either of the things you mentioned, is it possible/worth it to just replace the AC clutch and not the whole unit?

 

That is perfectly normal, the clutch CYCLING On & Off, while A/C is On.

You'd have to determine if clutch is actually the fubarbed component, if only wanting to replace clutch.
I suggest you ask around, and find a competent/honest A/C repair shop, locally.

Good luck.

 

Btw, if noise is not that obnoxious, you may get the Summer out of it. May?

 

RoadMattster, Did you turn the compressor shaft, or just the pulley? Pulley should spin freely & noiselessly. If not, the freewheel bearing is shot and WILL fail & take out your belt at some point. Some folks here know how to change that bearing; I don't. If it happens to me, a new compressor's going in.

 

Originally posted by Jimbeau:
RoadMattster, Did you turn the compressor shaft, or just the pulley? Pulley should spin freely & noiselessly. If not, the freewheel bearing is shot and WILL fail & take out your belt at some point. Some folks here know how to change that bearing; I don't. If it happens to me, a new compressor's going in.

And to take Jim's comments a little further, if you can determine that front Bearing is on it's way out, it's better to get it fixed or replaced before damaged internal compressor debris contaminates rest of A/C System.

 

In a very few cases, a little bit of oil charge could help. But that was mainly with compressors built in the old days when they were "built".