Tug on the belt to see if the spring-loaded tensioner pulley moves and springs back. If it sticks after moving and doesn't take the slack up when you release the belt, it should be replaced.
Sight down the edge of the belt where it goes around each pulley to see if it is not perfectly in line where it goes around all the other pulleys. If it is running off to the side a little on one pulley it will slide across it as it goes around. That will cause a squeal.
You can verify a belt squeal by dribbling a little water on the smooth back side. If it gets louder or quieter, the belt is indeed squealing but the cause still has to be located.
Don't use any type of belt dressing on a serpentine belt. Road dust will stick to it and form a gooey mess. That will cause a worse squeal later.
If it makes a chirping type of squeal, suspect dirt and sand particles embedded in the smooth side. You can often fix that by carefully holding the flat end of a file against the belt while the engine is running. If you see little sparks, that's the pebbles hitting the file. Wear safety glasses because those pebbles will be flying off. Do that until you don't see any more sparks.
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Monday, February 7th, 2011 AT 8:18 AM