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Jeep squealing/whistling

91K views 42 replies 25 participants last post by  tangofox007 
#1 ·
A little background..
My jeep has about 144,000 miles on it, I bought it used with almost all the stuff it has on it, already like that, so I don't know very much about all of it. It has been driving just fine, but it started making this weird whistle.
The problem..
It started making a whistling/ squealing sound, a real high pitched sound, and it only happens above about 20 mph when I press the gas pedal down to a certian point, it's not a metal on metal sound it's like an air-whistling sound. The pitch of the sound changes with how far I press on the pedal, and if I press the pedal down far enough, the sound stops, but then if I let back off the pedal a little, back to when the squealing started, it starts whistling/squealing again. But if I completely let off the pedal, it also stops. The pitch changing has no correlation to the rpm's, only with how far the gas pedal is pressed down. I know from looking under the hood I have a Afe cold air intake, and I have done a lot of searching to try to find an answer to this, I can't seem to find anything quite like mine, I have read that cai will make this noise, but why would it just now start doing it? So I went and tightened the hose clamps on the cai, and test drove it, with no change. It still whistled at certain points when pressing the gas pedal down ,above 20 mph. Because it doesn't make this sound while revving it in neutral, I can't find the exact spot where the sound is coming from in the engine compartment, but I do know it is coming from the engine compartment. What could this possibly be? Anyone had anything like this?
 
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#29 ·
This may actually be my issue, my idler pulley is a bit corroded/rusted and has a bit of a roughness to it so I would imagine my replacing it would cure my whistle, and my belt would probably be happy with a replacement pulley as well. Any idea how much and how difficult this is?

Sorry for the multiple images of the same thing... damn computer!
 

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#30 ·
Super easy just pull the bolt holding it on. Go to a parts store get a pulley about 15-20$ check the belt tensioner pulley also. Those were the two I had to replace. If that one is bad too pull the torx holding the tensioner on then take it off and there is a torx on the backside. Same thing get a pulley and replace.
 
#31 ·
the pulley in your pic (stationary pulley) is easy to change, if you have to change the tensioner pulley, its a little tricky. You have to line up the tensioner bolt housing and the pulley bolt when putting it back together.

these are the bolts that you need to get to in the diagram

the pic of the broken bolt (dont do lol) is the tension bolt and the square part is the housing the pulley bolt goes into. its behind the metal frame the pulley is on

you can see it if you climb under your jeep behind the front driver side tire.
 

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#33 ·
I'm having a similar issue. When the engine is all the way warmed up (210 deg) there is a horrible squealing sound when I come to a stop. As soon as I get over 5 mph the squeal stops. Even if I'm stopped and I rev the engine the squeal persists, only when I begin driving does the squeal stop. Is this a pulley issue?
 
#36 ·
Same problem as OP

Same exact issue as OP. Squealing on gas pedal accel until about 20-30mph. Just started 4 days ago and very loud high pitch. Only have 34k miles but been rough on the accelerator. Automatic. JK 2012 Sahara 2dr. I am not someone that can do the work myself, so would like guidance before taking to a shop. Thank you.
 
#37 ·
Airbox noise

98 jeep tj 4.0 112,000 miles all original has a loud low tone whistle coming from the airbox. When i hold my hand over the inlet it stops, but of course im just blocking off all the air. Any ideas why it would be doing this and how to fix. very annoying hard to hear all the other noises. lol
 
#38 ·
As others have said, it is definitely a vacuum leak. The question is where. Mine was unfortunately complicated. I replaced the exhaust manifold bought from NAPA (can't remember the manufacturer). As you'll see, the intake and exhaust share the same bolts and require that the manifolds fit together nicely.

Well.. in my case the exhaust manifold was casted poorly and did not fit exactly well with my intake manifold which meant the bolts did not fully pull up the intake to the head causing a vacuum leak. I had to modify the exhaust manifold to fit properly (using a grinder) which ultimately lead to me taking them both to a machine shop. I was able to get the noise to go away from my own hobo modification, but I wanted to fix it permanently so thats why I took them in. I've found that those casting are frequently sloppy which is resulting in poor pull-up to the head. If your previous owner replaced the exhaust manifold (which is a common replacement) this is very likely the problem.

As others have said, spraying the intake gasket with starter fluid while at idle will cause it to temporarily increase in RPM. Dead give away. Its not a ton of work once you know where the problem, but still a pain.
 
#39 ·
225k on a 97 2.5L have the same issue, but not constant. Squeal/whine will come and go - no relation it appears to heat or cold. Issue can happen either with engine cold or totally warmed up. Most obvious when it starts at a red light or something, but the first time I noticed it was on it's maiden voyage to the woods. Mostly highway driving there 70-75 MPH would start making the noise around 3k RPM or 65 mph. Downshifting into higher RPM's or coasting to lower RPM's seemed to stop it. After that the sound would come and go seemingly at random. Checked my pulleys and had a totally gunked up idler, cleaned that shiny and smooth, checked/tightened vacuum hoses etc. and tightened my belt.

Here's my problem - how do I find out what exactly is causing it if the sound isn't something I can reproduce (either standing still) or at will? I can't take my belt off and get on the highway or anything like that... It's been suggested that the problem is either a bad bearing in the engine, in the alternator or the oil pump but I'd hate to go throwing $100 here and there just to try and fix it with no clear path to resolution. I'm always worried that my belt is too loose though - is there a reliable way to check this besides "just push on it"? My TJ was a factory AC unit, but the PO bypassed the seized compressor with what looks like a shorter belt... I just pulled all the AC stuff out of it period.
 
#41 ·
@Big Bad John - I'm can't venture a guess at what you're dealing with. Iit does not sound symptomatic of the vacuum leak tho. The is very repeatable and occurs when the motor is not under load (idle) and does away as soon as you throttle it up. My guess is a bearing as well, particularly if it's spotty. Give it time, it'll get worse and show it's head
@dsheab I don't have an EGR on my motor, but anything that bolts to the intake can cause a vacuum leak. Best way to find them is with a bottle of starter fluid sprayed on every place that could be a leak until you hear the idle bump up temporarily.

btw.. old throttle body gasket is fine as long as it's still pliable. Mine was rubber bc I have Multi-port injection and I reused it more than once. If your injectors are on the throttle body, the gasket might be different, in which case I can't comment
 
#42 ·
2009 Jeep Wrangler - same squealing/whistling

SQUEALING AND WHISTLING (similar to the original post)....we just bought a used 2009 Jeep, off a lot, with 125,000 miles last week.....it's a good vehicle and we love it but as we are driving it around here locally, getting to know it and all it's personality, we have noticed the same exact whistling/squealing sound, a high pitched sound, that only happens when when I press the gas pedal down a little, then it goes away........as the original post states, it does not appear to be metal on metal sound..... it's like an air-whistling sound....."the pitch of the sound changes with how far I press on the pedal, and if I press the pedal down far enough, the sound stops, but then if I let back off the pedal a little, back to when the squealing started, it starts whistling/squealing again. But if I completely let off the pedal, it also stops. The pitch changing has no correlation to the rpm's, only with how far the gas pedal is pressed down".......

has anyone had a good easy resolve for this or know what I can tell them when I take back to the where I got it? I called them the day I drove it home and they told me to bring it in and describe what it is......

Please advise.

Thanks,
jec4jeep
 
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