another front end squeel thread

Have a constant high pitched squeel, very loud, from the front of the engine. Varies with RPM and under about 500RPM it's quiet. Does increase in pitch with RPM

Harmonic balancer is new, belt is new and tension is fine. Any ideas? It sounds like it's coming from either the idler pulley (88 motor) or the water pump. :flamemad:

Too high to be the alternator, too far left to be the PS pump. Anyone ever see these idlers go bad and squeel like a banshee?
Belt is tracking ok but I had noticed some noise at idle and figured the bearings on that pulley might be going south.

Philip
I am the service manager for a northern California shop that services Jeeps and I own an 87 XJ. I had a customer come in today with what sounds like the same issue, mainly a horrible underhood shriek caused by a frozen idler pulley.
I would inspect both pulleys/tensioners and the serpentine belt.
After we replaced these for our customer, voila, problem solved.
Good luck, and let us know how it turns out.
Thanks David

I would start the eng cold and rev it up so that the noise was vary loud! Hold the high idle up there for a good 10 sec or so and then shut the eng off.

Now, carefully touch every pulley on the jeep and when you find the one that is warm or Hot you have found the noise pulley.

If you can twist the serpentine belt more then a 1/4 of a turn then it's to loose and is more the problem then the warm pulley!

I just replace my belt several week ago and it started to squeal. cheeked the belt and it was loose, re tightened it and noise when away!

In my experience the water pump is more likely to rattle. Anyway, you can test that, because if it's bad it will probably wobble too. I vote for the idler pulley. It's pretty common, especially if you just replaced the belt and tensioned it well.

The pulley was shot for sure, gritty bearing feel. Somehow the PS belt had hopped one groove forward and was riding the edge of the pulley.

I do not know if I missed this last night or if the bum pulley caused the hop while I was driving it today due to poor tracking... but the rear PS pump bolt had backed out a little allowing some degree of flex, I suspect that's my culprit.

Just wish it had waited until a warmer night. I work 12 hour shifts and it happened mid work week so it was dark when I got home yesterday, it's possible under high rpm the PS pump flexed a little and caused the hop and I just didn't see it. Explains why the belt was plenty tight.

The idler needed to go anyway and it was only 16 bucks.