Finally got around to charging my AC in the Buick. Had them vacuume the unit then fill er up. When I first started the car it made a slight grinding noise from the compressor. When I turned the air on the noise went away. Turned the air off and it was quite a grinding noise. Drove the car about 60 feet and the noise stopped. Went to start the air again and it wouldn't work. The clutch wouldn't engage no matter what I did. I spent the next few hours on the web searching for a solution. I came across a guy who was bragging about this billet nose peice he put on his compressor. Same as the one I have. He went on to say how good it looked..bla bla bla...the last thing he said before he ended the video was to never over tighten the 3 screws the hold the billet peice on. If you do it bends the clutch and it will not engage. I took out the 3 screws and took off the nose peice and started the car..No grinding and when I turned the air on it worked perfect. I'm most likely going to put it back on but for now I'm thrilled that I don't have to spend another $700 on a new compressor... You would think the manufacture would give you a heads up about tightening the bolts to much. FYI