Hi guys,
This year I've noticed a metallic screeching sound when my A/C engages on my Altima. At first I thought it was a belt slipping, but I checked the tension on both belts and they seem ok. It happens mostly at about 2k rpm and above, and if I'm moving when it happens, it'll usually keep screeching until I put the clutch in and the revs drop.
My question is, is this a black and white case of a bad clutch, or could it be the compressor itself? I had it down to the dealer for a quick free diagnosis, and the tech figured it was the clutch due to it being stiff to turn by hand, but now that I think about that, if the clutch, ie the outermost part of the whole assembly is hard to turn, then wouldn't that mean the compressor itself is stiff inside? The actual pulley spins pretty easily so I'm thinking it's not the cause of the problem.
How does the clutch work? Is it simply an outer surface (connected to the internals of the compressor) next to the pulley, which is pulled into contact with the pulley when engaged? Would this screeching/slipping be doing damage to the friction surface of the pulley when it slips?
Thanks for any enlightenment :)