All of those are possibilities. Sight along all of the pulleys and look for one where the belt is peeking out to the side as little as 1/16". If you see that, either that pulley or the one right before it is turned or tipped due to a worn bearing. That most commonly happens to spring-loaded tensioner pulleys. When a pulley is tipped, even just a little, the belt slides across it as it goes around it. That will set up a squeal, but when the squeal goes away intermittently, it's usually due to a tension problem. With the engine off, obviously, tug on the belt. You should see the tensioner puller move, and it must return smoothly when you release the belt.
The belt could simply be worn too. The problem isn't wear that prevents the ribs from grabbing the ridges on the pulleys. It's that the rubber becomes hardened and slippery. Look at the cracks on the ribbed side. It is generally considered acceptable and normal to find up to one crack per inch. More than that is a sign it's ready to be replaced.
Sprinkle a little water on the smooth backside of the belt while the squeal is occurring. As a general rule, if a pulley is tipped, the noise will stop momentarily when the water acts as a lubricant. If the belt is slipping, you may actually see a pulley slow down. There's no force on the idler pulleys. It's the generator and power steering pump that take a lot of power. One of those may slow down when you run the water on the ribbed side of the belt.
Wednesday, December 25th, 2013 AT 11:37 PM