My car makes a squeaking sounds that is consistent with engine speed. It happens at idle, and I can hear it when I'm driving at low rpms. The squeak stops when I depress the clutch pedal, and resumes when I release the pedal. So I can easily deduce that something in the clutch is vibrating or squeaking.

I don't think it would be a throw out bearing since the squeaking happens when the clutch is engaged. What could be making the sound? And is it anything I should even worry about? The clutch works just fine and does not slip.

 

Any ideas?