Annoying "belt" squeal

chuck2000xj

NAXJA Forum User
Ok....I have a 2000 XJ (as my name eludes to) and for quite some time now I have been getting this horribly embarassing squeal that sounds like the belt. I have replaced the belt, replaced the idler pulley below the power steering pump, and have tightened bolt the tensioner bolts pretty tight. The squeal is present when I first turn it on and then stops after about 5 seconds. The time it is making the most noise is while driving and (now that its cold) turn on the heat or in the summer it was the a/c. I went wheeling 2 weeks ago and it seems to be squealing when I slow down for a stop sign or to turn the corner. I have to turn the blower completely off, start moving again, and then I can turn the air back on. Any ideas? Thanks
 
My 98 was doing the same exact same thing. But mostly with the AC on, finally my blower motor smoked, after changing it out it has never done it again.
 
Curious... I too have this problem ('98 sport). And my voltmeter drops to about 10/11 volts (normally 13/14).

I found if I turn the heater off and on a couple of times it goes away.


:dunno:
 
The serpentine belt on the Jeep 4.0 needs to be awfully darn tight to keep quiet.

Tighter than any other vehicle I've worked with in 37+ years.

Inspect belt and replace it with a Goodyear Gatorback if the current one has 60k plus on it.

If belt checks out, try tightening a smidgen.
 
Thanks for posting this. I have the same issue on my dads 2000 4 banger wrangler. Its getting so loud that I dont even want to drive it. Just like yours it used to squeal extra loud with the AC, then the heat.... now its just all the time :flamemad:

Last winter I was at college. My dad was driving and one idler seized and took the belt out with it. My dad was forced to have a mechanic replace both. The upper idler looks a little crooked to me.....and the belt seems to be shedding! The kicker is that there is only 40,xxx miles on the jeep!

I have a Gatorback, and 2 new Dorman idler pulleys sitting in my garage ready to go on. However, I was wondering if it could be other pullys on the system. Like could the water pump or alternator pully go bad?

2 years ago my dad had the ENTIRE AC COMPRESSOR replaced when the mechanic told him that was the issue :doh:. My dads the type who gets very frustrated with a vehicle, then drops it off at the mechanic and says fix this....
 
I have this problem as well on my 2000 xj. It use to only do it at idle, as soon as you gave it gas it went away. My belt came part way off the power steering pump and broke. I put a new belt on it now it happens all the time, I guess it's just not tight enough.
 
harmonic balancer is a known weak point on the 4.0L belt drive-- check and make sure it is not beginning to separate. It can cause all of the previously described symptoms.
 
how much of a pain is it to replace or is it just a unbolt the old one and replace it with a new one?
 
Harmonic Balancer....always inspect while your changing a belt. That is good advice.

As for belts. I went through belts on my Jeeps and my explorer. I have found that Napa, Autozone, Carquest belts all suck. Goodyear belts or Dayco makes a special belt for squeling...those Napa belts are the worst.

Avoid belt dressing.....makes stuff worse and eats belts. Also look for oil/coolant. Just my experiences.
 
X2 on belt dressing. That stuff is not made for serpentine belts. It worked "okay" for the old V-Belts, but was overused even with those. Serpentine belts are not V-Belts.

The Krikit II tension gauge is a great tool for getting belt tension right if you are unsure.

I really have good luck with the Goodyear Gatorback serpentine belt. Stretches much less than some of the others, lasts a good long time. Worth a few extra bucks.
 
I sprayed belt dressing on 2 days ago because the sound was driving me mad. Definitely helped.......

Could you go into detail about the harmonic balancer?
 
balancer is the crank pulley--it consists of two separate metal parts:

-the center of the balancer is a fairly light weight wheel that provides a hole for the mounting bolt and three smaller holes for a puller to thread into

-the outer portion of the balancer is your pulley grooves machined into an inertia ring

both of these pieces are attached and held together by an injection molded rubber layer that allows them to move "slightly" on that rubber and help absorb inherent harmonic vibrations from the engine.

As time passes, engine heat cycles, oil leaks, and constant movement deteriorate the rubber ring and allow the outer inertia ring/pulley to shift (usually toward the timing cover) and cause belt mis-alignment and squealing.

http://www.naxja.org/forum/showthread.php?t=928917&highlight=harmonic
 
It's on the front end of the crankshaft... not all that hard to find.
 
It's the BIG pulley (sheave) at the bottom, front of the engine, can't miss it. The front pulley at lowest part of the engine.
 
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