Hi everyone. I own a 1996 Jeep Cherokee with the 4.0 I6. I noticed I have a belt squeak and I have found that the belt is moving back and forth on the mechanical fan pulley. I have untightened the belt, and moved the belt slightly on that pulley, and it did nothing to fix the squeak. I have untightned the belt, tightened the belt and so on, and the belt keeps moving on that pulley. I have noticed that after the engine warms up, and if I shut it off and let it sit for a minute, then start the car it will stop squeaking, though the belt is still moving. Any tips on what this could be would be very helpful. Thanks!

 

It sounds like your belt needs to be changed , it mite have a a broken cored in it that makes it move on the pulley .

 

First I would look at the physical condition of your belt. Determine if it needs to be replaced or is still good.
Second... if still good... check the tension on the belt... you may have to adjust your idler pulley to get the correct amount of tension. That could easily be your "squeak" if it's not set correctly...causing it to slip.

 

If the belt is wandering on one of the smooth pulleys, as stated above, it is most likely a stretched or otherwise damaged cord internally in the belt. No more than a new belt costs I would just replace it.

 

Check the alignment of the power steering pump pulley. On my WJ, there's one bolt in the rear of the pump mounting bracket that bolts to the block and someone left it out, causing the pulley to move crooked and wear out one edge of the belt. This caused the belt to not track properly on the water pump. The WJ has a spring tension idler.

 

Aside from checking that the belt isn't starting to fail, inspect the harmonic balancer (aka vibration damper) to make sure the outer ring hasn't walked forward or backward.

 

Dont some of the idlers have a bearing that wears out?

I know I have 2 new spare pulley bearings anyway

 

Yes the idler pulley is just a single sealed ball bearing. I'm not sure how the fan clutch pulley is mounted. I have not had that apart yet but it is clearly not mounted on the water pump shaft.