Ok, so I've had this problem for a while. The belt only squeals when the a/c compressor is enganged (so when I'm running a/c or running the air to the dash vents). People have told me it's either oil on the that a/c compressor pully, or the belt is too loose and I need to replace the belt tensioner. I have a 2002 Dodge Ram 1500 that is the problem truck. The a/c compressor itself was replaced about 1.5 years ago when it siezed up. I recently replaced the belt and thats when it started to squeal (although it wasn't immediately afterwords, it was like a month or so before this started). My question is, if it is oil on the pully, what do you reccomend to remove the oil (i.e. using a solvent of some sort, just wiping it repeatedly, etc.), or if it is the loose belt, will someone please take a picture of the tensioner and have arrows pointing to exactly where the marks are that are supposed to show you when to replace it. I keep looking at the Haynes and the Chiltons manuals, but I can not see on the actual part what they are refering to as the wear indicator and stationary mark. Thanks!