Sight down from the highest run of the belt to the section between the lower pullies. If you can see the lower section peeking out about 1/8" compared to the section above, the spring-loaded tensioner pulley's arm is worn and the assembly should be replaced. That causes the belt to slide across the pulley as it goes around it. Also, tug up on the belt and watch that tensioner. It should move back smoothly when you let go. Oh, ... Do that with the engine not running!
If the belt feels a little loose, try pushing on the tensioner pulley. Sometimes rust builds up on the pivot and they get tight. That prevents them from applying enough tension on the belt.
Don't use any type of belt dressing on serpentine belts. Dust will stick to it and become embedded in the smooth backside. Not to ask a stupid question, but are you sure it's the belt and not a squealing alternator or power steering pump bearing?
A stethoscope works nicely in locating which is the offending pulley. Look very closely at the ribs to be sure they match perfectly with the pulley grooves.
If all else fails, try a belt from the dealer with a "Q" at the beginning of the part number, (quiet).
Sunday, February 28th, 2010 AT 10:21 AM