Hi everyone, a few months back I replaced the serpentine belt on my 1996 Cherokee with the I6 4.0 liter. Shortly after replacing the belt, the belt started squeaking pretty loudly, I used the car for months with the belt squeaking and finally decided to resolve the issue. I tightened the tensioner which only solved the squeak for about a week. The belt starting squeaking yesterday, and it seemed to quiet down after a few minutes of driving. I went back out today, and it starting squeaking again. It sounded like it was coming from the passenger side, right around the AC compressor and the alternator. I tightened the belt more which didn’t seem to do much for the squeak, I also checked for wobble on the pulleys, there wasn’t any. I decided to spray a bit of water on the belt and it got rid of the squeak. But I’m sure it will come back after a few minutes. Should I replace the belt because it was slipping for months? Could that be the issue I’m having? Any info would help, thanks!

 

Dont use water or belt dressings. They are a temporay "fix". When you checked the pullies, they didnt wobble. But did any feelrough, sound dry or have any resistance to them? Are any of them rusty, where the belt rides? Or any old rubber residue baked onto them? The belt takes a certain amount of tension on these things. More than one might think. Some can do it by feel, some use a gauge. A Krikit II tension gauge, from Gates (#91132, i think it is) is what i use. New belts are 180-200 lbs, and a used belt is 140-160 lbs.

This is for a 99, but you get the idea.

 

Sorry to disagree with my counterpart, but, you should indeed use water and water only to diagnose belt squeak. Per the Gates official videos on how to do so, you have already done the 'test'. Spray water on the belt, if it stops squeaking, you have a pulley alignment problem, period. Period.
So I just went through this very issue with my 97 grand, and I can tell you what mine was and likely your issue is, ..the pulley below the power steering pump is misaligned. (Plus my belt was worn out, and it's near impossible to tell this.)
Edit: I see you have the XJ, a totally different setup than the ZJ, so my problem won't be your problem, but likely something similar knocking alignment off.

Upon examining, the bracket that holds the whole assembly of the pump and pulley is misadjusted where it bolts on at the bottom to the engine block, causing the idler pulley to kick out at a slight tilt. If you look closely facing the engine, down, you can see it.
The fix is to loosen that bolt, and somehow move the bracket. The hole in the bracket is intentionally egged, to allow for this adjustment.

 

spray the water on the pulley centres, not the belt, just a smidgeon, if the noise stops, its a pulley

 

Also check that the harmonic balancer isn't seperating and the outer section walking in or out. The face across the outer section, rubber middle, and inner hub should be even.

 

Change the brand of belt. My wife's 01 does not like Gates belts. WE put a different one on and no squeal.