I had my AC serviced a few days ago. On the drive home I noticed a fairly loud whine, sounds like it could be belt related. Gets louder when I accelerate and goes away completely when AC is turned off. Is this cause for a return trip to the shop to complain/have fixed, or is this a normal post-AC service sound that will subside after the AC is run for a bit? ('91 X with 16K mi, no other known mechanical issues).