2003 Volvo s60 engine squeaks not on cranking it but after driving for awhile . Just replaced serpentine belt but problem persists

What is your question?

High pitched squeaks from engine that seems to follow the vibration of the car. Doesn't happen at start while car is cold. Squeaking starts only after car has been driven for a while and continues till engine has been turned off and has had ample time to cool down. Replaced serpentine belt 2 weeks ago but it's still squeaking

What makes this problem better or worse?

It's worse once engine warms up or air compressor turns on

How long has your 2003 Volvo S60 had this problem?

2 months