Sight down the belt in three places. Next to the upper engine mount, the tensioner pulley, and the crankshaft. If you placed a straightedge along all three, they should be in straight alignment. If the section of belt on the tensioner sticks out even 1/16", there will be a squeal. Check that the tensioner is seated squarely and there's no dirt or other debris behind the mounting plate.
No anti-squeal chemicals should be used on serpentine belts. Dirt will stick to the belt and make the squeal worse.
Chrysler used to offer new belts with a part number that started with the letter "Q". We joked that it stood for "quiet". Don't know if that's true or not but it solved a lot of squealing problems.
Sunday, March 22nd, 2009 AT 6:11 AM