Misalignment of the drive belt pulleys can cause a chirping or squeaking noise from the drive belt.Google+
Car Problem Reports
Chrysler PT Cruiser Drive belt noise due to misalignment of drive belt pulleys
Chrysler PT Cruiser Problem
Engines Affected: 2.4L 4 Cylinder, 2.4L 4 Cylinder Turbo
Average Mileage: 102,222 mi (70,000 mi - 140,000 mi)
Visitor, 2003 Chrysler PT Cruiser, 2.4L 4 Cylinder Turbo, 90,000 mi
The belt driving the AC & Power Steering has chirped/squeaked for a while. I thought it was the tensioner, so I replaced it with a new one, plus a new belt. Same noise.
I then squirted conditioner lightly right at the AC pulley while running, and it went away. Of course within a day it was back.
Not crazy loud, but definitely annoying.