Noise Problem

I need help with a noise problem I have been having. It started a few weeks ago, but the car has been ok. The sound has been there every time I drive the car, kicking after the car warms up, but then periodically phasing in and out. It sounded to me like something being kicked around by a spinning part. I looked at it and it seemed like the noise was coming from the left side, around the AC compressor. I took the car in to the mechanic last week to have some other stuff done, and asked them to take a look at it. They told me that the sound was coming from the driver side and that it sounded to them like a loose wrist pin. Then, after taking it off the lift, the AIR pump seized, and the belt snapped. Since they put the new pump, there has been no sound. Basically I want to know if there is any way the two sounds can be confused. I don't fully trust the mechanic's compentcy since the car came back to me with a loose upper radiator hose and accompanying coolant leak. I'm afraid, because a loose wrist pin is a pretty serious problem, and I don't want to drive it too much if that's the case. Any opinions?