Ive been hearing a squeaky belt rotating kind of sound in my car. It stops when I switch off the AC. And somehow it has a connection with the clutch which I don't understand. When I apply the clutch the sound pops up. But this sound comes once or twice in a week only, sometime for short duration and sometimes throughout the drive . So the problem is when the service guys check it, there won't be any issue & later when I drive it pops up. What might be the reason?