'92 E300 AC "Chirps"

I tried search--thought this would be common. My office mate has the above car. AC quit, so he didn't run it for 10 days

He takes it in, gets a charge, and it blows cold now. However, when he first engages the AC it makes a brief squeaking noise.

Loose belt?

TIA

[Arthur Dalton]

Comp clutch has rust coating from non-use.
Will seat in after a few..

Originally Posted by tkamiya

Only chirps when compressor is on, correct?

.

Yeah, that's correct.

Thanks for the reply.