idler pulley/serpentine noise

idler pulley/serpentine noise


Klamath Falls,OR
1986 CJ-7, 258 - 6, tranny-T5, D300 transfer case, D30 front, D20 rear.
Hi all, Im new to the group here, but have been looking for a little while for info on my new, to me, 86 CJ7. I found a sweet heart locally and picked it up for a project with my son, 13yrs old. Its almost all original with the exception of a lift and 33's, 237K miles. runs great.
Issue: I replaced the serpentine belt and the new one immediately started squealing. Ive tried belt dressing, nope. Adjusting the idler pulleys alignment, nope. Tightening/loosening the belt, nope. A little bar soap on the belt has helped but only temporarily.

Question: one of the idler pulleys is plastic, and one metal. The plastic one looks like its not original and is a little wobbly, minimally, and appears to have been melted slightly by rubbing on the outside washer/plate that is held by the mounting bolt. Is the plastic pulley original? and why would soap quiet the belt if the pulley is messed up???
I don't have the same engine, or have I ever had luck with serpentine belts, but noticed no one had commented on the post with ya.

I would say double check the belt good with the existing one. You can also reinstall the old one to see if it's the same thing. (still making the noise) and therefore rule out problem with new belt.

The plastic pulley may be the problem. Never have (again) seen or had experience with it myself.

Now are you sure it's not the Water pump or alternator? I know it doesn't seem likely they'd start making noise just as you change the belt, but it is "possible" I suppose.

Anyways, Hope some others will see this and comment, with more helpful advice :cool:

And :ww: to the site bud!

~ JR
I have never seen a serpentine belt on a 4.2. Not saying they didn't do it but it may all be aftermarket.
Thanks for the response fellas, its a California jeep that escaped to freedom in Oregon and has the stock serpentine set up. I rebuilt the plastic idler pulley yesterday and fixed any wobble, I'm certain it's aftermarket and will order a OEM metal replacement soon, I also picked up another belt, Goodyear gatorback "quiet belt" just in case.
My son did his first oil change, tune up and timing check last night and it runs much better. No squeal from the pulley so...standing by

Jeep-CJ Donation Drive

Help support by making a donation.

Help support by making a donation.
This donation drive ends in
Top Bottom
AdBlock Detected

I get it, I'm a Jeep owner and ad-block detectors kinda stink but ads are needed on this site. This is a CJ site, all the ads are set for autos (some times others get through.) I cannot make them just for Jeeps but I try.

Please allow ads as they help keep this site running by offsetting the costs of software and server fees.
Clicking on No Thanks will temporarily disable this message.
I've Disabled AdBlock    No Thanks