94 Jimmy has loud grinding noise from front of engine

My 1994 Jimmy always ran a little louder than usual but just last week it got very loud. I started up my Jimmy one day and the engine sounded so loud I knew something was wrong. I opened the hood and heard a very loud grinding growling noise coming from the front of the engine. The serpentine belt rotates fine and looks good, however it seems that a bearing or pulley has gotten worn out which is causing the loud noise. I sprayed some WD-40 around it to see if the grinding noise would decrease. It did not. So I put my head up close to the noise to pinpoint the problem. Strangely when I turn on the Air conditioner or the defroster the loud noise decreases to a moderate noise. I notice there is a clutch connected to the AC pump that rotates and stops when you turn on the AC on. This is a problem I want resolved immediately I just need some advice to what the problem might be. Possible AC pump, new pulley, bearings, serpentine belt?? It sounds like it will cost me around 400 to 500 dollars to have fixed. I don't think I need a new alternator. Any response would be a big help.

The only way you'll find out, is to remove the belt and rotate each pulley by hand, including the idler and listen feel for a rough bearing.


From your description, the finger points to the AC pump.