Serpentine belt squeak!!! XJ

shelby27604

shelby27604

Well-Known Member
Joined
Jun 6, 2013
Location
Efland NC
Just did a full cooling system tune-up, including a serp. belt and tensioner pulley. I fired the jeep up, ran great but I noticed a squeak every time the white lettering on the belt went over the tensioner pulley.

Scuffed some of the paint off the pulley
Put belt conditioner on the belt
swapped old pulley, old belt, new pulley, new belt in every combination....squeak is still there, and it is BAD with the AC.

Tried every conceivable tension on belt and pulley bolt...no change.

The only thing I did to the AC was blow some of the dust out of the clutch....did I force some crap into the clutch? What are the odds I can take this apart and clean it up? If not, anyone got a lead on a clutch kit, I can't find one and would rather not buy a $250 compressor just to pull the clutch.

While I am at it, what is the best way to set the proper tension on the 4.0l belt? Is there a tq. spec on the pulley, or just enough to take the wobble out?
 
When you say the squeak is bad with the AC, does that mean after when it is engaged, or while it engages (a chirp?). I doubt you did anything to the AC clutch, as it either engages or it doesn't engage. The most load the compressor will add to the belt system is when it is engaged, obviously.

I'm just puzzled about why you're pointing at the AC compressor, when it sounds like the compressor is just calling attention to a symptom that is already there because of the extra belt load when the clutch engages.

Did you replace the water pump if you did a full cooling system tune-up? I don't know what kind of tensioner it has, but did you replace it if it's a hydraulic tensioner?
 
Last edited:
Full flush of the system and new water pump.
The tensioner pulley is mounted to a bolt that you tension manually, it isn't a spring loaded tensioner.

I did the flush in a couple of stages, the last stage was with a new WP, new pulley, OLD belt, and no thermostat. With the final fill I put in the water pump and the new belt. With the new belt, I could see that the squeak (no AC) correspond to the exact moment the white lettering on the belt came in contact with the pulley (assumed it was a pulley or belt related).

When I turned on the AC with all new parts in place the squeak became CONSTANT and LOUD....as in you can't stand near the engine with the hood ukp without hearing protection loud.

When I put the old belt and old pulley on, the squeak with NO AC is gone, turn on the AC and it is right back to constant and deafening.

Before this, the AC worked fine, no issues. The squeak being constant makes me think the clutch isn't 100% engaging and is instead dragging.

I pulled the belt, the pulley spins freely, no bearing noise or wobble. I can spin the clutch / compressor by hand, it isn't easy, but it isn't hard or notchy. It also looks like the compressor is new within the last ~2 years.
 
Clutch kit:

UAC CL4691C
Sanden 65816010

I'm still not convinced this has anything to do with the AC, because you have a squeak when the compressor isn't engaged. I think the load from the AC is just making things worse, or maybe something to do with the new water pump.

I'm starting to thing you may have a problem with tensioner misalignment if it's a smooth (not ribbed) tensioner and it squeaks when the lettering goes over the pulley. Pulley isn't installed backwards, is it? The belt shouldn't squeak on the tensioner unless there is tensioner drag, and there should be nothing that would cause tensioner drag unless the tensioner is misaligned or the tensioner bearings are seizing, and the bearings would not be the problem in this case if the pulley is new.

Did the belt conditioner make things worse? That stuff will sometimes make a squeal a lot worse.
 
Pulley is not on backwards (shaped like a bowl, flat portion of the bowl is toward the radiator)
Belt conditioner made no appreciable change, except getting my hands all sticky.
No noise or issues from that water pump during the last flush, and at the moment, the noise goes away with AC off.
Everything tracks with the belt centered on all the smooth pulleys (WP and tensioner).

Going to pull the AC clutch and see what I can see tomorrow.
 
All I can say is that this is timely. @trailhugger's Jeep has a problem where - once in a while - you start it up, and the alternator won't turn. The belt squeals, shut it down, restart, it's fine. I figured the belt was too loose, so I tightened it up, only to get what sounded like bearing noise from the alternator (confirmed with the stethoscope).

Figuring the alternator was crapping out, I pulled the belt off of it, only to find that everything spins silky-smooth. I decided that it could use a new belt. That was yesterday. I haven't bought a belt for it yet, but then you posted this.

So let me know what you figure out, then I'll do the same.

Random question - are they "good" parts? Gates or similar? Or just whatever Autozone puts in a box? I had a problem with the Exploder where the spring tensioner danced around and squeaked. Replaced it and both idler pulleys, got no improvement. A few years later, I replaced it all again, and it finally fixed it. The second time around, one of the idlers had bearings that were obviously bad. My guess is that they were shit to begin with, and the random lag they put on the belt was causing the chirp and the dancing idler.
 
Tensioner pulley is AC Delco
Belt is Continental
Water Pump is Gates

These were the best brand names I could grab locally. The napa belt was probably a rebranded Gates, but it was twice the price of the continental.
 
Also, maybe get another belt that hasn't had dressing/conditioner on it. I know it's new, but I don't like any kind of lubricating anything on belts, as that can make a squeal hard to stop.
 
Well, you were all wrong.....the solution was to TIGHTEN THE BELT!

it is absolutely crazy how tight this belt has to be....the advice of get it to the point where you think it is too tight, then tighten a little more is spot on! I got it tight, then made 1/4 turns of the tensioner while the engine was running, and manually running the throttle (low rpm squeak was easy to get rid of, cruising rpm was another 3+ turns of the tensioner.

@Fabrik8 the dressing I used was super sticky....In the past I have used the stuff that is slick, and softens the rubber.....I was not a fan. Fortunately as I was pointed in the wrong direction, I only put dressing on the smooth side of the belt.

Thanks everyone for telling me the same thing, made me feel like I was on the right track while I was over tightening the tensioner and wearing a face shield while doing it.
 
makes you wonder how worn the V groove pulleys are, belts grab on the sides of the V, even serp belts. multi grooved to offer even better grip.
Curious what a replacement grooved pulley for say the alt or power steering might look like compared to existing.
 
There is still black paint in the grooves, so I don't think there is a lot of appreciable wear. I can tell the compressor and alt. have been replaced at some point, likely the crank is the only grooved pulley with much wear, and that gets almost a 180deg. wrap/contact patch.
 
Buy one of these belt tension measure devices and you are good to go.

f2b34ec83bee897a684f7b881bbd177e.jpg



Sent from my iPhone using Tapatalk
 
Any idea what the "correct" belt tension measurement on an XJ belt is? Everything I read said that the jeep spec was too low, and that Jeep Tech's at the dealerships just set them to not squeak.

FYI to anyone tossing a new belt on, I have had to increase the tension every other time I start the jeep......I guess this is why every other manufacturer put a spring loaded tensioner on serpentine belts.
 
shelby27604 said:
Any idea what the "correct" belt tension measurement on an XJ belt is? Everything I read said that the jeep spec was too low, and that Jeep Tech's at the dealerships just set them to not squeak.

FYI to anyone tossing a new belt on, I have had to increase the tension every other time I start the jeep......I guess this is why every other manufacturer put a spring loaded tensioner on serpentine belts.
Click to expand...

IIRC 70-90lbs. But if the belt isn’t slipping and there is no squeaking then why tighten it anymore....


Sent from my iPhone using Tapatalk
 
NickMaul said:
IIRC 70-90lbs. But if the belt isn’t slipping and there is no squeaking then why tighten it anymore....


Sent from my iPhone using Tapatalk
Click to expand...

The squeak comes back, seems like I drive it 20 miles, let it cool and the squeak comes back. Takes about 1/4 turn of the tensioner and I am back in business. For the moment I am chalking this up to initial break-in stretch.
 
I would have an awareness that the a/c compressor could be going bad and requiring extra torque to turn until it fails and locks up
 
anything is possible, but the entire AC system looks to have been replaced recently, the entirety of the interweb seems to agree the XJ belt needs to be unreasonably tight or it will squeak. I will update the thread when you prove me wrong though, and I melt to death in this awesome summer heat!
 
Back
Top