I have a 1995 F150 with a 302 engine. I have had noise coming from the (serpentine) belt almost the whole life of the truck and I do not know how to eliminate it. The belt is in good shape and I can't see it rubbing on anything to cause the noise. It is most noticable when first starting the engine. After driving for a while, the noise will sometimes go away. The noise is really loud and high pitched and changes with the RPM of the engine. What do I need to do or check? Thanks

 

Here is an easy test, start the truck, get some wd-40...water will work as well...spray the belt...sides-top-under...squeal goes away...replace the belt and the sound will go away until the belt wears out again. If sound doesn't go away, spray some wd-40 on the pulleys bearings, alternator-a/c-belt tensioner one at a time, if the sound lessens or goes away completely, I would think its one of the bearings going, more likely than not you just need a new belt, from my experience the serpentine belt will look fine but begine to sqeal after a fair amount of miles are put on it. Good luck hopefully its just the belt

 

Just had to put a new belt on mine.... I hated to, b/c the belt on it looked good, it just wouldn't SHUTUP! So, I replaced it "under protest", and no moe aquealing. So, I am Happy

 

Well, I am leary about replacing the belt because the squealing has happened since the truck was only a month or two old. Maybe I did get a bad belt from the factory.

 

There is a mark on the stationary part of the belt tensioner, that mark should fall within the range marked on the part of the tensioner that moves, this give you an easy way to tell whether the belt has stretched in excess.

Any foreign fluid on the belt could make it squeal.

Not to be too sarcastic but its been 9 years, if it was an alignment issue with the pulleys it should have shown up as a thrown belt or at least one with irregular wear. Its suggested that the belt be checked or replaced, according to haynes, every 7500 miles or 6 months, its been 9 years probably time to replace that belt.

My belt begain to squeal on one truck at 30,000 miles , replaced it and the sound came back at 80,000 replaced it and its still fine....Just a thought..good luck

 

I've heard that a belt will squeel sometimes when new because of the molding process allowing a buildup of materials on the side of the belt, making it rub on the pullies.
My late uncle was a long time mechanic, he would take a handfull of sand and dribble it on the belt as the motor idled. It would ususally quieten down. I use a variation of that. I'll take a piece of snadpaper and fold it in a way that I can let it rub on the sides of the belt. It usually works
Clint

 

I have never heard of that before, I will give that a shot myself, the next time my belts get noisy.

 

a good friend of mine,and a long time mechanic.showed me a neat trick to stop a squealing belt.with the engine running,take a small handful of powdered ajax,or comet.throw it on the belt where it meets the pulley.repeat two or three times.this will deglaze your belt and stop the squeal...wayne

 

I replaced a perfectly good, but old, Motorcraft belt with a Dayco "Polycog" one. Squeal gone. This is after I replaced the worn idler pulley without solving the problem.

Jim