Loud squeal at startup, and when using heat/ac

OK, after attempting to clean my engine last weekend, I now have a new problem: when I start my XJ, there is a loud squeak/squeal coming from the engine (serpentine belt?) at startup. It will go away but when I give it gas, it will come back.

Also, when I turn the heat or A/C on, the same loud squeal will last for a long time. It sounds horrible and I'm thinking it's a loose belt or something.

I'm going to take it over to a full-service gas station that my friends own and see if they can tighten it for me.

Do you guys (and gals) think that's the problem?

Tightening the belt will probably work, but is it possible you just got some kind of cleaner on the belt or pullies?
Billy

My first thought is a loose, glazed, or slipping belt. Glazing you can see with the naked eye ("glazing" on a belt shows as shiny spots,) and you should replace the belt and give each of the ribbed pullys a slight hit with either Scotch-Brite or a "soft" (brass or bronze) wire wheel. A glazed belt slips, and will usually start to glaze the pullys as well.

No need to take it to a service station tho - a belt is easy enough to change. If you don't feel up to handling it yourself, post a call for help in your local Chapter asking for some help. This way, you can have someone show you what to do for next time, you'll learn a lot more, you'll spend a lot less, and you'll definitely come out ahead (split a pizza or something to pay for the job.)

Suggestions on belt purchase would be either Gates or Goodyear - I've used both for the last 20-25 years with consistent good results. OEM and most "house brands" are made by Dayco, and Dayco belts tend to delaminate and fall apart (if all you can find are house-branded belts, ask who makes it. If they can't tell you, go somewhere else. Checker/Schuck/Kragen are all made by Dayco. CarQuest is Goodyear, and probably NAPA as well - but I haven't checked.)

I had the same issue this summer whenever the A/C kicked on. Replaced the belt with a Dayco and it has been fine since.

FWIW all Advance Auto belts are made by Dayco; both the cheaper Drive-Rite and the "premium" Dayco.

JeepFreak21 said:

Tightening the belt will probably work, but is it possible you just got some kind of cleaner on the belt or pullies?
Billy

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No b/c I only used water from the hose.

IllianaXJ said:

I had the same issue this summer whenever the A/C kicked on. Replaced the belt with a Dayco and it has been fine since.

FWIW all Advance Auto belts are made by Dayco; both the cheaper Drive-Rite and the "premium" Dayco.

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Yeah I had a similar issue 2 summers ago when I'd turn the A/C on. I had a new serpentine belt put in.

However, I don't remember it being this loud or lasting this long.

Try tightening the existing one if its in good condition.

If you get a new one make sure you get it tight or you'll have the same problem. Buying a Kirket II tension gauge from Napa helps alot as the belt needs to be much tighter than you think.

get a can of wd 40 or something like it. start your jeep and when it makes that sound spray it on one of the exposed pullies. If it stops the sound then it is the belt. shut her down and then just tighten it up. you said you replaced it a few years ago so probably just needs tightened.

Didn't you just have an issue with the power steering pump a couple of weeks ago? If so and you had the belt off, it's probably not back on tight.

I had this same problem with mine squealing when the a/c first cut on, then when I got it back from the body shop a couple months ago it would chirp at start up because they didn't have it tight enough. A lot of people (myself included) don't realize just how tight it needs to be. If memory serves, it's something like 180 ft-lbs, but i'm only about 80% sure on that number. Tightening it up stopped the noise, but I went ahead and replaced it anyways as it had some glazing on it.

As mentioned, if the belt you have on now is in good shape, snug it up and see if it goes away. If you think the belt should be replaced, be it from excessive glazing or overly cracked and brittle. New belt from NAPA shouldn't run you more than $25-30 if I remember correctly.

time for a new/tightened belt

I had a similar prob with squeeling when a/c defrost is used, turned out to be the compressor

bcmaxx said:

I had a similar prob with squeeling when a/c defrost is used, turned out to be the compressor

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that is why i suggested spraying (lubing) the belt with a little wd40. It gets a dry belt a little bit gummy wihtout that horrible belt dressing crap! it doesnt last long but will tell you if getting a new belt or tightening it will work. otherwise it is something else like you suggested.

Belts on the 4.0 need to be quite tight to keep the squeals/chirps at bay. Tighter than any other vehicle I've ever owned. Tension gauge helps. Tighten a smidgen at a time as of course, too tight isn't good either. I've had the best luck with better quality belts like the Goodyear Gatorback. Stay away from the el-cheapo belts; you get what you pay for and the better ones are way less prone to noises and future glazing. If the belt is older, I'd just replace it instead of trying to tighten your current one. A mechanics stethoscope is also helpful sometimes in isolating noises along the serpentine belt route. Good Luck!