Just bought a Jeep with a squeak and its driving me nuts

Hello all,

I just bought a 2000 jeep cherokee off a buddy, 150k on the engine. When I bought it, it would squeak a little on startup and when cold. No big deal, Ill just put a new belt on it. That made the squeak worse, I must be loading the bearings somewhere. So I checked with the belt off and found the waterpump loose. So I put a new thermostat and waterpump on this afternoon. Turned it on and still squeaks, so this i evaced the ac and pulled the clutch off and pulled the sealed bearing open to shoot some grease to see if the bearings were shot. I start it up again and it still squeaks, but I noticed the battery wasnt charging. So I tighten up the belt a little more and squeak went away. Hurray I thought, So I went out to dinner and came back. I fired up the jeep and the squeak is right back to where it was before i replaced the waterpump.

Anyone have any insights?

I'd think alternator since the battery wasn't getting charged, but they don't usually fail to charge from a bad bearing.

The harmonic balancers on these things are notorious for failing and it will evidence itself with a squeak/squeal that you cannot get rid of. Check to see if the rubber between the inner and outter rings has begun to deteriorate.

Most times when I get a squeak it is from dirty pulley or a dirty belt. Coolant seems to be the worst, it gets sticky especially when it's cold and squeaks.

I rub the smooth pulleys with a 3M pad lots of hot water, scrub down the belt with mild soapy water and then rinse with hot water and use a brass brush and hot soapy water on the grooved pulleys. Mild soapy water and lots of hot water to rinse, I use a garden watering can.

Belt tension is important, too tight and you can screw up the water pump bearings, too loose and it squeaks, especially with a new belt.

My quick setup is usually 3/4" of play on the longest stretch of belt, using moderate to hard pressure from my thumb.

Check the alignment of your haromic balancer and see if the outer ring isn't migrating on the inner ring.

I've had good luck with a silicon spray specially formulated for door rubber, I found it at a local gas station. Regular old silicon spray is not recommended for rubber, it's on the label. They ought to relabel this stuff squeak away and market it as belt dressing. It softens the rubber up well and has never seemed to hurt anything for the years I've been using it.

Really not much resistance on the alternator pulley and the belt makes a sharp bend there, not the spot you'd expect the belt to slip. How hard does it turn by hand?

How do I say this without offending?

Seriously?

Get a 3' piece of rubber tubing, stick one end in an ear and then move the other end around the engine--engine running--and ISOLATE THE SQUEAK.

It really is that simple.

PS: please refrain from engaging clothing, hose, or flesh with moving engine parts.

joe_peters said:

PS: please refrain from engaging clothing, hose, or flesh with moving engine parts.

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that takes the fun out of everything..... but is definitely good advice:roll:

joe_peters said:

How do I say this without offending?

Seriously?

Get a 3' piece of rubber tubing, stick one end in an ear and then move the other end around the engine--engine running--and ISOLATE THE SQUEAK.

It really is that simple.

PS: please refrain from engaging clothing, hose, or flesh with moving engine parts.

Click to expand...

not to offend you but I tried it and doesn't work. as you know all the pulleys are right by each other. I did find if I sprayed some water on it this morning it went away for approx 1 min and came back. I did this 2 or 3 times and it finally went away at idle only slipping if I goose the throttle.

Have you set the belt tension by guessing, or with a tension gauge? When I use my gauge and tighten to spec, I end up tightening it WAY more than what I would otherwise think is reasonable. Serp belt tension is a lot higher than you'd expect.

I set it the same way I would set a piece of equipment. straight egde and ruler. 1/2 deflection

Why not just crank the radio? So much easier than locating the squeak

I did run some sand paper on the idler pulley on the waterpump after the water to clean up the surface. I also notice a very slight notch worn into the face of the pulley. feel it with a finger nail, probably could measure it with a micrometer. maybe that's enough to cause the belt to only ride on the edges at that point.

That shouldn't be it - it's a rubber belt, it'll conform a bit. You definitely set the tension wrong though - the 1/2" deflection method doesn't really work well, since the tension in the belt that results in 1/2" deflection depends very heavily on the length of the span you're testing and also the amount of pressure you apply. Try using a belt tension gauge (Krikit IIs tend to work well on serpentine belts) and see how that works. I forget the spec but it's in the FSM.

I have used the tension guages before and found them pretty useless. I'm not sure why jeep doesn't use a spring arm tensioner that every other manufacturer uses. ill probably just tighten it a few more turns, if not I order a dayco belt. I always try to buy usa made belts and this one is stamped usa but it feels cheap.

I wish they'd use a spring arm tensioner too... would make things way simpler. IIRC they did on V8 ZJs, actually.

IIRC Later model xjs use them. I do believe that the belt tension guage is a good idea. I shold probably break down and buy one.

h20pumper said:

I set it the same way I would set a piece of equipment. straight egde and ruler. 1/2 deflection

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Since no one yet has offended anyone and apologized beforehand anyway...what "piece of equipment" are you referrring to. The belt tension on a 4.0L Jeep serpentine belt ? Or a swamp cooler?

The tension on a 4.0 serpentine belt is specified as 180-200 ft. lbs for a new belt and 140-160 for a used belt. The specifcation for a swamp cooler might be a little looser.

A Kricket II gauge (for a serpentine belt, not a v-belt) will set the "correct" tension on a new belt. If used correctly that is. Then after a day or two...the belt is used. The "spray water on it" test proves out that the belt is too loose. Just sayin'

four_shot said:

IIRC Later model xjs use them. I do believe that the belt tension guage is a good idea. I shold probably break down and buy one.

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My 2000 tensions off the PS pump pulley, same as any other Jeep I've seen, a spring tensioner would be outstanding.

I just use my ages old calibrated thumb for ~1/4" deflection (by eyeball guage) between the PS and Waterpump pulley with light pressure. Have yet to burn anything out yet with multiple jeeps. Hell, I just replaced a perfectly good water pump this weekend and it was tensioned the same way 7yrs ago ... so it must work for me. The final test is tightening the pulley bolts, it should slip just as you reach torque.


Have you checked to see if the idler isn't doing the squealing?

SUCCESS!!!! I sanded the face of all the idler and tensioner pulleys then i replaced the cheap belt with a dayco and the squeak is gone. :loveu: