Belt Squeal

[jay79cj7]

This might be a dumb question, but here it goes...

I changed my serpentine belt on my 4.0L about 2 weeks ago. Goodyear Gatorback. Not too long after, a loud, high-pitched, very annoying squeal greeted me as I started it up. It has been doing it whenever the engine is cold ever since. The noise only lasts through the first minute the engine is running at worst, and then it goes away. Usually its one long squeal, but sometimes its broken up into several short ones. I haven't been able to locate the noise when I look under the hood while starting it. The engine sounds completely normal when its warm. This noise is irritating the heck out of me and scaring people in parking lots. How do I get rid of it? Is this something stupid, such as, the belt is too loose or too tight? My buddy said I might have a bad belt, but how would I tell if it is or not?

Thanks everybody.

 

[laneiac]

PARTING OUT

My girlfriends jeep did the same thing, I changed the belt and made sure it was set at a good tension, not to tight, but not too lose, and now it works just fine. Dont spray any belt dressing on it, it will make a mess and can damage your belt. I would play with the tension of the belt before changing it again...

 

[jay79cj7]

That was quick! So when you had this happen, was your girlfriend's belt too loose or too tight? Since it only does this when its cold, it makes it hard to adjust and then test to see if the change worked, so I will try to go the way you went first. I didn't know how tight to make it, so I just felt the old belt, and tried to make the new one about the same.

 

[K_K_PSI_GUY]

The belt is probably too tight. Try that. Also, make sure the belt is on there correctly.-al

 

[graewulf]

rule of thumb for a serpentine belt, you should only be able to twist the belt 1/8-1/4 turn.... if tightened properly... less is too tight, more is too loose... sounds like its loose, it will slip until everythhing spins up to match engine

 

[kraken]

Something else to consider. On my last car (not a Jeep) I had the the same thing happend. new belt high pitch sound when i started it. one morning I went to start it, got the sound along with a thump. It ended up being the berings on the idle pully, they froze and snaped the belt . just something to think about if the changing of the tension dosent solve the problem.

 

[ecor]

I was going to suggest the idler pully also, one of the things that people over look is that when they offroad in mud and sand that gets up into the backside of the idler pully. When you change your belt you may be moving the tensioner into dirt and starting problems with the bearings. Remember to wash out your engine compartment before starting any work under the hood...

 

[laneiac]

OK, I'm impressed.... (see pics)

My idler pulley actually broke off the mount a while back, had to get a new one for 20 bucks. Its been my experience that a loose belt will squeal more than a tight one, but either way is not good. Ecor and Kraken had a very good point about the idler pulley, that little bastard can get stuff in there and stop free spinning, the belt may just drag it along a little.

 

[exjay33]

re:

Give it a little shot fo belt dressing .

 

[jay79cj7]

On the advice of a friend, I sprayed the belt and pulleys down with a silicone spray. No more squeaking for about a day, and now its back. Whatever it is, the spray masked it for a little while. I still haven't messed with the tension, but thats on deck for tomorrow. The belt seems plenty tight, so I will try loosening it a little.

 

[jay79cj7]

Well, I think I fixed it. I loosened the belt a tad and it got alot worse, so then I tightened it a bit past where it was before, and the sqeal seems to have gone away. At least for now; it has fooled me before. Anyway, thank you for your responses. I am glad it turned out to be something so easy. Funny how one person can look at the belt and tell you its too tight and the next can look at the same set-up and say its too loose.