While messing around trying to diagnose my overheating problem on my 1994 miata, I found that my AC clutch occasionally would either lock up and / or fail to disengage. When this happened it looked as if the belt (or something else) was smoking near the AC clutch. I had some problems in the past with the clutch failing to disengage in the past, so I bought a replacement from Rock Auto.
The AC clutch looks like it has been on the shelf since 1994 in a basement in the south, next to the beach, after a flood. I'm sure it will buff out... The mating surfaces don't look too bad, so I suppose it is ok.
In the instructions it said to diagnose the reason for failure prior to installing the clutch. One reason for failure could be the compressor.
How does one check if the compressor "is good"? When the belts weren't "locking up" the system had cold air. Is that good enough, or is there a "quick diagnostic" that can be done? As of this writing, the clutch is not in, since I'm waiting for some belts and an idler pulley. I'd be pretty torqued off to have to buy a new compressor (which probably comes with the clutch pre-installed) after buying the clutch.
