Update! Outside tonight shining flashlight at compressor to confirm turning (it was) there is a black greasy ring around the frontmost part of the compressor. In front of the pulley I suppose I would call it the clutch hub? The part that doesn't spin when the compressor isn't running. I shined my light straight down, and also saw what looked like a thin greasy string of like material on the front engine splash pan. Bad/disintegrated clutch? I'm sure it's not a good thing. Hmmm, so would that be the compressor appeared to be engaged and the disc-fiber material seized to the nose piece giving the illusion that the compressor itself was spinning. I guess I'm trying to menatally discern if the compressor may be okay and only the clutch bad. What's next? Remove the clutch and investigate further?