Hello,
If I turn on the air conditioner at the current temperatures (

to

0°C) to prevent the windows from fogging up, quite loud noises come from the engine compartment.
As soon as the air conditioning compressor engages, the ribbed belt (presumably the small one connected to the air conditioning compressor) starts to squeal. After a 15-minute drive, the noise diminishes somewhat, but it is still present.
The V-belt is still relatively new; it was replaced a year ago.
What might be the reason for that? What can I do?
(1997 Passat 3B AFN (81kW TDI))