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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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#6 ·
Thanks for the replys, I really hope it's not one of those driveshaft joints or u joints, cause I would have no idea how to fix that, and that sounds expensive to fix. Could it really be that? The strange thing is that it only makes the whistling/squeal sound when the gas pedal is in a certian position, so that being said would there still be the possibility of a driveshaft/ u-joint problem?
 
#15 ·
Yeah, very annoying. I tried to record a video of the sound with my smartphone while driving, but the whistle is so high pitched the microphone couldn't even pick it up! And my dad couldn't hear it very well so maybe it's something so high pitched that only young ears can hear it good. Anyways it's super annoying being that high pitched. Cleaning the cold air intake didn't change it at all. So maybe it's a vaccum line leak? Would the pressure in vaccum lines change with the amount of throttle applied? Cause if not, there must be some component of the intake that's causing the whistle.
 
#16 ·
Gogetem1994, Mine doesn't make the sound in 4th gear either(which is the overdrive gear according to the reading I've done online) so that's really weird. Or I might not have pushed the engine hard enough in 4th, cause of the speed limit being 50, and cops always crawling all over the road.
 
#18 ·
I went out in the garage tonight and sprayed most of the little hose connections I could see connecting to the intake. I didn't have any carb cleaner, but I read that wd-40 would work too, so I tried that. After spraying the connections I could see, none made any change in the idle speed. Are there any specific ones I should try that I may not have checked due to my lack of knowledge on vacuum lines?
 

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#23 ·
Ok, I went and bought some carb cleaner. I couldn't get any idle change while spraying. I sprayed all the areas shown in the photo, 3 elbow connections on the side of the intake manifold, around the throttle body area, the two hoses on top in the back of the manifold, and the crack where the manifold and headers connect to the engine. None made any change in the engine idle. Any other places I should try?
 

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#25 ·
Whistling Noise Solved!

I know exactly what is wrong with your Jeep. For the past three years, my 02 Jeep Wrangler X has been giving off this horrible whistling noise like nails on a chalkboard. It always started once I let my foot off the accelerator while I was on the highway. Always starting when I got over 50 mph. At first I simply could not figure out what the problem was and by the time the third year ended I had almost given up hope. The noise was unbearable. People could hear me coming down the street a mile away. It was even worse at stop lights.

Finally about a month ago, my jeep started acting up. There was no power in my acceleration. With each passing day, my jeep got slower and slower. I couldn't even get over 50 mph on the highway. My check engine light read P0432 - Main Catalyst Efficiency Below Threshold.

Obviously something was blocking my exhaust system from working properly. So yesterday I took apart my catalytic converter and discovered something extraordinary. One of my converters near the engine had completely disintegrated into the pipe and was now clogging up my rear converter causing the cats to become red hot while I was driving regularly. Due to the cats being red hot it melted an O2 sensor wire causing the engine code and the engine itself to run rich. After driving it for three years running rich it caused many problems including:

The idler pulley, tensioner, and the belt to go bad.

Washers on the fuel injectors to go bad with the valve cover gaskets top and bottom.

All PCV valves to go bad.

The battery died due to the delayed starts caused by the clogged cat.

Once I replaced all the washers on the fuel injectors the whistling problem was resolved temporarily for about five miles then the whistle returned. Although frustrated I knew now that I was on the right path. But before proceeding any further with the whistle I decided instead to fix the main cause of all my problems: the catalytic converter.

We put degreaser and soap and water through it and nothing came out the other side. Therefore to remedy the problem I "increased the flow" of the catalytic converter with a hollowed pipe. Once reassembly was complete I took my jeep out for a drive. And believe me when I say “what a difference!” My power was back. My jeep itself felt like it had been reborn. The only problem remaining was still the whistling noise. Only this time it was worse than before.
Opening the hood we finally discovered the culprit – the screw that holds down the intake and exhaust manifolds on the front of the engine near the first fuel injector!
Once sprayed with Tri-Flow "penetrating lubricant" and tightening of the bolt it resolved the issue. The whistling was gone. In conclusion, all of the residual problems which I had to fix originated from my catalytic converter going bad. You may not have all of the issues that I had but regardless I would urge you to check for these problems.
 
#26 ·
Whistling Noise Solved!

Opening the hood we finally discovered the culprit – the screw that holds down the intake and exhaust manifolds on the front of the engine near the first fuel injector!
Once sprayed with Tri-Flow "penetrating lubricant" and tightening of the bolt it resolved the issue. The whistling was gone.
I didnt go as in depth as you did chasing the Whistle, but I did go straight to your Whistle fix, and tightend the screw holding on the intake and exhaut manifolds. No such luck for me though. I even went further and tightend all of the intake screws.

My annoying whistle happens only on the freeway above 50 MPH, and at a very precise throttle postion (usually at my cruising speed). Its not too terribly loud, but definitely noticable on the highway. GOGETUM94's idea with the radio seems to help, but when it comes to little noises, I this complex to not stop until I find the noice.

Anyone with other suggestions?
 
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