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serpentine belt ?

jeep ride

NAXJA Forum User
98 xj 4.0L with air Engine started making squeaking noise when I looked at engI noticed the serp belt is walking off the front of the pulley that the fan blade mounts to I removed the belt spun all pulleys by hand didn't hear any noise started engine for a few seconds no noise from harmonic balancer couldn't see any wooble in balancer reinstalled belt as I started eng. belt started to walk off same pulley any ideas?
 
They looked ok but I will look at them again tommorrow.
 
Check the pulleys like suggested.
But it could be as simple as tension.
I found in a '96 I used to own I could use the cheapest belt possible, do the tension by the "Yeah that looks about right" method and be good to go.
My '00 on the other hand needs the better belt. I use a Napa one which is just a rebranded Gates.
Also it is very particular on the tension being just so. I bought this:

https://www.amazon.com/Gates-91132-Belt-Tension-Tester/dp/B000CRDLZM

Now I used the "Yeah that looks about right" method. 1/2" of play, being able to just turn the belt 90 degrees in the longest section between pulleys, etc. Then checked with the gauge. It read 100. If I remember correctly should be between 140 and 160 for a used belt and 180 to 200 for new. It was amazing how far I was off with the "Yeah that looks about right" method.
 
Check the rear fan clutch pulley bolts, I've had them loosen and fall out before. Now I Loctite them.

Check the pulley by checking the side play. Grab the pulley and twist it sidewards gently, you can feel the bearing play if present. The fan/clutch is even easier, use the fan blade to check/feel the side play click of bearing play.

Do the same with the other pulleys. especiallöy the one just before the fan pulley.

You might as well check the harmonic balancer bolt while you are at it. I've also seen them come loose.
 
Over tightening the belt is also bad, it can trash the water pump bearings.
 
98 xj 4.0L with air Engine started making squeaking noise when I looked at engI noticed the serp belt is walking off the front of the pulley that the fan blade mounts to I removed the belt spun all pulleys by hand didn't hear any noise started engine for a few seconds no noise from harmonic balancer couldn't see any wooble in balancer reinstalled belt as I started eng. belt started to walk off same pulley any ideas?


The Harmonic Balancer doesn't need to be wobbly to have failed. The outer portion often slips forward or backward with respect to the inner piece. Usually looking at the rubber section will tell you if it's slipped.
 
Looks like harmonic balancer is bad lots of cracks on the rubber that holds the two half's together plus it has moved forward ever so slightly.
 
Looks like harmonic balancer is bad lots of cracks on the rubber that holds the two half's together plus it has moved forward ever so slightly.
Just in case, check the center bolt on the balancer. I've seen that bolt back out on more than a couple of occasions. I'm really careful now about torquing that bolt to spec. and using a dab of Loctite on the threads. The last time I caught one of those bolts backing out it was only in there a couple turns from catastrophe (I got lucky).
 
Just in case, check the center bolt on the balancer. I've seen that bolt back out on more than a couple of occasions. I'm really careful now about torquing that bolt to spec. and using a dab of Loctite on the threads. The last time I caught one of those bolts backing out it was only in there a couple turns from catastrophe (I got lucky).
That is what I was thinking I would try first
 
I had this problem a few years back ('98). The harmonic balancer has a hard rubber insert that goes bad and it goes out of plane, however slightly. Will cause the belt to throw. Not too hard a job to replace. Got one from rockauto and it's been fine since. Wasn't a big job to replace, but you need a puller to get the old one off and proper torque the new one on. I used a simple craftsman rubber strap wrench to keep the crank from turning when taking out the old one and torquing back in the new one. Can't remember the torque value but if you don't have let me know and I'll get it from my FSM.
 
Look at the front face of the AC Compressor Pulley. You should see three (3) small
leaf springs connecting the pulley inner hub and outer ring. Check the springs for
any tiny-teeny hairline cracks, or separation. Anything goofed here will cause the
outer pulley ring to become misaligned. The misaligned outer ring may also rub
against the clutch face (internal) and cause a metallic squeal; and may cause the
serpentine belt to walk while running.
 
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