My 99 cherokee with the 4.0 squeals a bit on start ups already replaced the belt and still squeals...at least I have a new belt right lol. But when I go searching for the idler pulley I keep getting different part numbers not sure what is the correct one thanks in advance.

 

Is the belt tight enough?

 

Yes it is. I checked that too.

 

What kind if belt did you put on? Mine was doing same thing put a dayco on and no more noise

 

Yeah I picked up a dayco

 

With your belt off, you need to check all pulleys and make sure they are all ok. Pay special attention to the harmonic balancer as when it starts to separate, it can be hard to tell. I chased a squeak for months. After a months or so, the belt would shred. I thought all my pulleys were good. I have a parts XJ so I thought I'd try replacing the HB. It hasn't squeaked in months now and no more shredded belt. My old HB was just BARELY starting to go. Even with a good straight edge it is hard to see.

 

It was the idler pulley: ) thanks for the help