Topic: Strange Squealing noise, need help with diagnosis.

[Duff5484]

I have had a strange squealing noise for some time now.  Begins after the engine is hot and only squeals when I take my foot off the gas.  The sound seems to come from near the intake/exhaust manifold.  It will squeal when idle, out of gear so its not the tranny/gearbox.  the second you apply pressure to the gas, the noise instantly goes away, at the same time it returns the second you release pressure, also it will squeal at any rpm you are at once you release your foot from the gas. 

I am going to replace my exhaust manifold gasket this weekend as that is my first guess, i will also closely examine my idle pulleys, however, myself as well as several mechanics has looked at this problem and we are at a loss of words.

Any suggestions would be appreciated.

[jfrabat]

Maybe the 4 squirrels are complaining?     Sorry, I could not help myself!!!

[Jeffy]

Serpentine belt?

[aw12345]

Intake vacuum leak is a classic sign of it whistle while decelerating or idling, that is when intake vacuum is highest.
Spray intake with water or brake cleaner and listen for a change in idle speed to zero in on the area where the leak is

[Duff5484]

Intake vacuum leak is a classic sign of it whistle while decelerating or idling, that is when intake vacuum is highest.
Spray intake with water or brake cleaner and listen for a change in idle speed to zero in on the area where the leak is

Tried spraying brake cleaner over all the vacuum lines as well as around the TB, not so much as a hiccup, its a 95 2.5L which significantly has fewer vacuum lines as opposed to my 89 2.5L


The squeal is not coming from the belt Jeffy, however, for the sake of trial and error I plan on replacing the belt.  I figure I will start with the cheapest part, the gasket being 15 dollars, and work my way up from there.

Thank you very much for the responses and would still greatly appreciate any suggestions.

Duff

[Jeffy]

Tried spraying brake cleaner over all the vacuum lines as well as around the TB, not so much as a hiccup, its a 95 2.5L which significantly has fewer vacuum lines as opposed to my 89 2.5L


The squeal is not coming from the belt Jeffy, however, for the sake of trial and error I plan on replacing the belt.  I figure I will start with the cheapest part, the gasket being 15 dollars, and work my way up from there.

Thank you very much for the responses and would still greatly appreciate any suggestions.

Duff

Just be careful taking the exhaust manifold off as the studs on the ends can be prone to snapping.  I'd do some more testing before taking the manifolds off.  Maybe use a dowel to listen for the squeal?

[Duff5484]

Just be careful taking the exhaust manifold off as the studs on the ends can be prone to snapping.  I'd do some more testing before taking the manifolds off.  Maybe use a dowel to listen for the squeal?

Yeah I'll be sweating when I first turn the bolts, it scares me every time    Although it will be easier this time since I have my air tools, the last few times i replaced gaskets i only had hand tools, not fun. 
 
When the squeal first started, one of the first things i did was test the entire block, tranny&TCase with my metal pry bar....nothing.

Thanks again

Duff

[rubberducky]

Maybe pull your throttle body off and check all the channels and stuff for buildup of gunk. With the blow by I had with the factory airbox oil would just stay in the box so I had to clean the intake every so often to stop a horrible sucking noise. Reminded me too much of a past girlfriend jk. My idler pulleys just went out they just sounded like a spinning bearing. Then there is always your throw out bearing, but thats to much of a deep metal sound. maybe your spark plugs need a new car! Mine do. 

[Duff5484]

I did some more research on the forums and found a previous posting on here....http://4bangerjp.com/forums/index.php/topic,1023.msg13768.html#msg13768 

I went outside, got the engine to squeal again, then put all my weight on the intake manifold and for the first time, i got the squeal to change pitch....it was the gasket.   I took it all apart this weekend and when i went to start it yesterday the jeep would turn over but not start.  After an hour double checking everything, over, and over again, my cousin ended up being the one who noticed a sliced wire.  Somehow the Crank Position sensor got cut off at the T-case.   

So for the time being my Jeep stays in the driveway while i wait for the sensor in the mail...local shops want $65 dollars for it when its $25 on Quadratec.

Just have to be patient for the time being.