High Pitched Noise

B

bandit71

New member
I am having a problem with my 2004 Jeep GC. There is a very high pitched noise coming from the engine compartment on the drivers side. You can compare the noise to an electric very high pitched whine. It only happens when letting off the accelerator(in park or driving). When giving it gas it immediately goes away. The pitch of the noise does not change at all. It is consistent no matter the speed or turning. I used a stethoscope but could not isolate it. It sounds like it is coming from the power steering pump or AC compressor area when I'm above that spot in the engine compartment but not sure. I am suspecting bad bearing in one of them but am looking for a second opinion and if there are any easy fixes that do not involve removing either. Any diagnostic ideas?

The belt has been recently replaced. The noise appears to be getting louder over time. First noticed it this summer.

Thanks
 

Can the pulleys be greased without having to remove them?
 

I have had no issues with temp. I went and listened again and can swear it is coming from around the power steering pump but when putting a stethoscope on it I can not isolate it. I took it up to Autozone and of course the sound will not replicate while they try to listen to it. Seems like it takes a few minutes of driving before it starts. Once you park it goes away after a few seconds and cannot be made to come back until you go drive again. This is frustrating.
 
Will. Take a. STAB. At. This. Whine. Noise. First. - which. Engine. Do you have in. This. Jeep? How. Many Miles? My. First. Guess. Would be. The Pulleys associated with the. Serpentine Belt! 1. Idler. Pulley. 2. Belt Tensioner. Top two culprits. You mentioned the. P.S. Pump. - Maybe. Does. The. Pitch. Of. Noise. - Change at. Idle or. LOW. Speeds. When. YOU. TURN the Jeep?? Might. Want. To. Change out the. IDLER. Pulley. - - I. Think. They are. Like - $ 20 or 25 ! Pull. Serpentine - Inspect. For. ODD. Wear. Patterns. - - TURN. All. Accesories. By. Hand. - - LOOK. For. Any. Rough. Bearings! (Rotate - feel for. Rough spots). Try the. Idler Pulley. - Check out the. Belt. Tensioner. Too!! Just a few suggestions! Good. Luck. JB
 

jimbob: is has the straight 6 in it and it just crossed over 100k in miles. I bought an idler pulley and tensioner b/c it is the easiest to change and like you said the cuplrit a lot of times but I have not put them on yet b/c everytime I listen it just does not seem to be coming from there. It is definately on the driver side which is opposite of these two pulleys. I heard the slightest change in pitch yesterday as I was sitting in my driveway revving it then letting off right away to hear it. Very very suttle change as the whine first comes in when letting off the gas and it settled into idle but for the most part it is a constant pitch. No change when the wheel is turning. New serpentine belt a few months ago. I am taking the belt back off to today to free spin the pulleys and try to get some more clues. One more thing to note, my power steering fluid was a little low a couple of days ago and I topped it off. At cold engine it was just above the bottom do not cross line on the stick. Did not take much to bring it back to the "cold" level on the stick. Not sure if that helps give any clues but thought I would mention. It did not change anything with the noise adding fluid.
 
These. Types of. "Whineing. Noise". In. The. Engine. Compartment - Can. BE HARD to. Isolate! True? There. Are a. Whole. Host of. Suspects: 1. Idler Pulley 2. Belt Tensioner. 3. Pwr Steering Pump 4. AC. COMP (bearing\clutch) 5. Alternator (BRG) Whew ! What. A. List! What's. More. - with. The. ENGINE. Running. - - Noises. Are. HARD. To. Isolate! The. Stetoscope. Was. NOT. A. Bad. Idea. - But, I. Prefer - A. 4. Foot. Length. Of. Hose. (3\4 or 1 inch)! With. The. ENG. Running. - Use. The. HOSE. (1 end in ear) - - CAREFULLY. Probe. With. The. HOSE. To. See IF. You can. Isolate. The. SOURCE of noise! This. HAS. Worked. For. Me in the Past - In THEORY. The. Culprit. Shoild be. LOUDER. Than. The. OTHERS! That is. Diagnostic Tool #1. Number. 2. Is. To. Pull. The. Serpentine. Belt - Inspect. It- THEN. Manually. TURN. All. Pulleys. And. Accessories! Do. They all. Rotate. Freely ? Any. Grinding or. Excessive. Play??? You. Have. To. Make the. Call ! Hope. This. Helps GOOD LUCK! JB
 

Jimbob, i got your pm but they will not let me respond until I have 10 posts. I appreciate your help. I took off the serpentine and spun all the pulleys and heard nothing out of the ordinary and they all spun fine with no lumpiness or grinding. I changed the idler pulley since I was in there and already had one bought but it did no good. I like your hose idea and am going to try to find a piece to use today. I could not spin the water pump so that could still be on the culprit list but the noise is not coming from that area(or so appears) so still focusing around the power steering pump. My problem is that I get about 60 seconds once I park it until the noise goes away on it's own. I have to go out and drive for 5-10 minutes again to get it back then park and listen again. Frustrating. If I break down and have to take it to a garage it will take them a long time to go through this routine and try to isolate with only 60 seconds of time to look at it each time.

54cj3B: my power steering was low(down to the low line at cold temp) but i filled back up and it made no difference. I have tried spraying some lithium grease between the pulley too and it does not help.

I do not suspect vacuum hoses but am going to do a thorough inspection of all those again too.
 
As. You. Have. Discovered. - these kind of high pitched noises - can be hard to track down! (Doubly hard when intermittent!) If. You. Can. DO. The. HOSE. Trick (be careful) IIt. May. Lead. You in. The right direction! Did. The Serpentine Belt appear normal when you. Took it off? No unusual. Wear pattern? It. Could still be the : BELT. Tensioner - Do you have. A. New one to. Try? How about the AC Comp? Does the AC work normally? When. The NOISE occurs - have. you tried Turning the AC - On and Off? Any change?? I have heard of. Cases. Where the AC Comp caused this TYPE of problem! I think the H2O. Pump. Can be. Put at the. Bottom of the List. Pwrer steering pump and ALTERNATOR - still. ON the list! Near the Top of list with Belt tensioner. Do all Accessories - FUNCTION NORMALLY? ALT. Charge. Batt. Normally? ETC. Have. You had a SECOND. Party. (Mechanic). Or. Any one. Else. LISTEN to the. Noise? Get another OPINION??? Might help. Tough NUT to CRACK! JB
 
When using the hose, it seems like I got closer to the noise. It got louder when I snaked it under the power steering pump (which is right over he ac compressor too). Nothing really under there though. Serpentine looks normal. Belt tensioner is on opposite side noise is coming from so do not think that is it. Cannot get AC to engage. Suspect b/c it is too cold out. All pulleys sounded ok when freely spun with belt off.

On another thought, I am starting to wonder if this is indeed a vacuum leak. I pulled the hose off of the pcv and blew into it(sits on top of the valve cover) to see if I could hear any leaks and it sounded like air was coming out around the side of the valve cover. Hope this is not a dumb question, but does that sound normal? Air was definately coming out. Not exactly where I think I hear the high pitch noise coming from but in the general vicinity. Starting to wonder if this noise is bouncing around in there and not coming from where I think.
 

Hey did u end up finding the culprit... I have the same exact sound... it's driving me nuts I've checked the manifold for cracks ac compressor power steering pump didn't check vacuum lines though any help would be beneficial so I don't go nuts lol? Thanks in advanced
 
Hi, I'm new here and have the same problem!! Have a 2013 sport unlimited, under 10k miles and started to hear this sound a few weeks ago. It happens intermittently. I've been to the dealership 3 times, no one can figure it out. What was the end result with yourS??
 
It ended up being the first manifold bolt, It was loose all I did was tighten it up n sound was gone instantly.... being that ur truck is new I would leave it at the dealer n have them deal with it n demand a rental until they figure it out... damn dealers don't want to do anything anymore but bill u 😠... but thank that there r for us like this to help people like us when needed....👍
 

Thanks - yeah, I've already done that 2 times. 1st time was a couple of weeks ago when I had to take it in for the recall on the power steering fluid line, they supposedly checked for the sound but were unable to reproduce it. A day or 2 later the sound started up again and I just went to the closest dealership, when I got there the sound had stopped, after about 15 minutes of idle it started up lightly again but once the guy opened the hood, the noise stopped. I then made an appt. (it was last Friday) and went back, my truck was there from 9:30am-2:30pm with no resolution. They did however update some software and apparently the power steering fluid was low (I guess someone messed up when I went in for the recall and didn't fill it back up after doing the work and flushing it all out) of course the noise started up lightly on my way home from the dealership, on and off all day Saturday and now has been quiet since. I'm noticing that it happens mostly on really hot/dry days. Sounds weird and might just be coincidence but it's true. Anyhow, I'm determined to discover what this is and have it fixed. It's driving me nuts! I might have to wait until it starts to happen more often though before taking it back in again...
 
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