Noise coming from AC clutch on a brand new AC ompressor kit

[Ryan Gregg]

I have a 1999 GMC Sonoma SLS with the 4.3L V6 and I just bought a brand new AC Compressor Replacement Kit and had it installed by a local mechanic. The AC works great, but after leaving the shop I noticed a metallic rasping noise when the AC clutch is not engaged. What could be the cause since the kit was brand new when installed? Any help would be greatly appreciated 

[Jsdirt]

Sounds like the clutch air gap is set just a hair too tight. There are little shims (washers) that you can stack, or remove, to get the clearance correct. I forget off the top of my head what it's supposed to be - .015"-.020" rings a bell, but I might be confusing ignition points for that spec, since I've been doing more of that on small engines lately than A/C work.

 

It may wear in with time and go away, depending on how tight it is. If the gap is too wide, you can get to a point where the magnetic field will not pull the clutch in. When that happens, a sharp tap on the compressor will engage it. You don't want it that wide.