My 1996 Civic often makes a short squeaking noise when the a/c is on and I release the accelerator pedal at 4,000+ rpm. This happens even if the engine is in neutral gear. I don’t think it’s the a/c belt because as far as I know the belt turns even when the a/c is off. Could it be the a/c clutch perhaps? The car has a B16A2 engine.

 

Replace and tighten the A/C belt. Then go from there.

 

Why would the belt only squeak when the A/C is on? Would I have to refill the system with refrigerant after changing the belt? Thanks.

 

It's the only time when the compressor clutch engages and places force on the belt.

Only if the refrigerant charge is low.