Squeal at startup

[hear]

I'm having a brief squeal right at startup. It usually goes away within a second or two, but occasionally lasts ~10 seconds. It never comes back while driving, but comes back just about every time at startup.

The serpentine belt is about 6 months old, when I changed my water pump. The squeal started at that time. I'm thinking my idler pulley is the problem, but that's really just a guess. Looking for help diagnosing.

 

[Winks42]

You can probably find out where the squeal comes from if you have a buddy start the jeep while you are under the hood. You can use a mechanics stethoscope or just a skrewdriver against your ear to pinpoint the sound. While you are there just make sure the belt is on nice and that it isn’t too loose or too tight, should be able to twist it to 90 degrees with a good amount of resistance

 

[Jerry Bransford]

Sounds like it could be the idler pulley bearing. What year is your TJ? Early models have a screw adjustment for belt tension, newer models have an automatic spring-loaded belt tensioner. And please complete your Profile, that's where we go to find out information about your Jeep before answering questions. Model year, engine size, which transmission, etc... everything you know about it.

 

[Gollywomper]

Very wheel could be a belt adjustment. How is the belt tension?

 

[hear]

Sounds like it could be the idler pulley bearing. What year is your TJ? Early models have a screw adjustment for belt tension, newer models have an automatic spring-loaded belt tensioner. And please complete your Profile, that's where we go to find out information about your Jeep before answering questions. Model year, engine size, which transmission, etc... everything you know about it.

I swore I had done that, just did it (again?). It's a 97. Regarding the belt tension, are you thinking its over or under tensioned? Is it weird that it squeals for a second and then goes away?

 

[Jerry Bransford]

I swore I had done that, just did it (again?). It's a 97. Regarding the belt tension, are you thinking its over or under tensioned? Is it weird that it squeals for a second and then goes away?

Thanks that it's a '97 helped which confirms you have a manual belt tensioner that is located on the power steering pump mounting bracket. It's the long screw, it's 3-4" long IIRC. The belt should be tight enough that you can barely deflect it 1/2" or so by pressing on the belt hard with your thumb between its two widest support points.

 

[hear]

Thanks that it's a '97 helped which confirms you have a manual belt tensioner that is located on the power steering pump mounting bracket. It's the long screw, it's 3-4" long IIRC. The belt should be tight enough that you can barely deflect it 1/2" or so by pressing on the belt hard with your thumb between its two widest support points.

I know how to tighten it, just didn't really know how tight was tight enough. Sounds like "pretty damn tight" is the spec here? I don't think I have it as tight as you describe.

 

[Jerry Bransford]

I know how to tighten it, just didn't really know how tight was tight enough. Sounds like "pretty damn tight" is the spec here? I don't think I have it as tight as you describe.

As described is how tight it should be.

 

[ColoJeep]

As described is how tight it should be.

Jerry be right !
Tighten that rascal up as described, and no more squeal at start up !

 

[hear]

Well I tightened it up, although It was pretty tight already. The problem was when I started it up to move it off the street to work on it after it had been sitting for 48 hrs....it didn't squeal, so I can't definitively say I've fixed it. I've started it 3 times since, and it also didn't squeal. So maybe. I have way too much scientific method in me to be satisfied with this.

 

[ColoJeep]

Well I tightened it up, although It was pretty tight already. The problem was when I started it up to move it off the street to work on it after it had been sitting for 48 hrs....it didn't squeal, so I can't definitively say I've fixed it. I've started it 3 times since, and it also didn't squeal. So maybe. I have way too much scientific method in me to be satisfied with this.

Great to hear, loose belts squeal more when cold. But in Texas cold is a relative thing
There is a SLIGHT chance that the belt could be worn from slipping too much while mis adjusted.
and you should replace the belt. However it is unlikely this is the case.
Sorry to throw another outlier into the " scientific method "

 

[hear]

Drove it a couple more times today, no squeal. I'm reasonably satisfied that this is solved. Thanks for the help everyone.