Last week I started getting a noise from my AC Compressor (or clutch). I squirted it down with some Silicon Lubricant and that seemed to help a little. But yesterday it really started making a horrible knocking (grinding) noise. The AC Clutch seems to be coming apart from the compressor. The noise (grinding) seems to goes away when I completely turn OFF the A/C or defroster. It does not make noise on the VENT however.
Can you tell me if this the Clutch or should I replace the whole Compressor to be safe?

 

Sounds like your A/C compressor is failing/shot. Normal cause of failure is BLACK DEATH caused by compressor wear. These are WOBBLE PLATE pumps with 5 aluminum pistons. The compressor wear is normally caused by moisture in the system. The factory fill oil is a hygroscopic oil which absorbs noisture and travels thru the system. This inturn reacts with the oil, freon and heat which causes a caustic issue which then causes internal corrosion, this crud flowing thru the system. This crud is then carried thru the compressor and makes it way to the orifice screen. The screen filters out the crud, but plugs up causing oil starvation, which in turn causes compressor wear and failure.

If keeping the vehicle, I would replace the compressor, condensor, dryer/accumulator and orifice. Flush the the evaporator and us a NON-Hygroscopic oil like POLYMAX2.

 

I have a '99 w/ DOHC engine. I just recently had the same issue (grinding, etc). My pulley bearing finally gave out and froze up. I will warn you that this compressor is not the easiest thing to get out. I know they recommend replacing everything, but I just replaced the pulley and clutch assembly. If you can turn the compressor, then you probably don't need to replace it. From memory, here are the steps to get the thing out.

1. Evacuate the refrigerant.
2. Drain the rad coolant.
3. Remove the lower rad pipe (to get to the lower mounting bolts on the compressor).
4. Remove the upper rad pipe (to get to the upper mounting bolts on the compressor).
5. Remove both electrical rad fans.
6. You basically have to fish the compressor across to the driver side and then up and out.

I also remember removing a bracket to the thermostat. You'll figure it out, but the key was to remove both fans and snake it up closer to the driver's side.

WARNING...There is a metal water inlet pipe that appeared to be severely corroded. It is metal with 2 rubber ends. I figured I would just replace this since it was corroded and in the way, so I just cut the rubber ends. This is a dealer only part and will cost you upwards of $200 to get it replaced. So be cautious.