mikeybonz

Hey guys i have a 2000 xj 6cyl 4.0, Recently since its been cold in Ny i have relized a whistling sound coming from the engine area while under way. This only happens while i'm driving the truck cold and once up to temp 210 it goes away. It will also go away if i come to a stop light, then start up again. Kinda like a high pitched whistle, Noise wont happen in park but only while driving until the engine reaches temp, then its gone no sound.


Doesn't sound like it could be a pulley but i'm not too sure. Could this be my WATER PUMP on its way out? No issues with overheating or going above temp.

Also should NOTE, the last person to do labor on my truck installed a thermostat that instead of using the gasket for the thermostat used blue corking to seal the thermostat.

Any help or ideas of what it could be would be great. Just kinda clueless of where it can be coming from.

Thanks Mike

extrashaky

Possibly an intake leak. A lot of people have had a whistle when the intake manifold wasn't seated properly or the intake manifold gasket wasn't sealing properly. Listen for it around the manifold toward the rear of the engine.

mikeybonz

i have tried but the noise/whistle only happens while the truck is driving and not in park or at idle in drive. the whistle always goes away when the engine gets up to temp.

I've pulled over on a cold day after first hearing it ( when the engine is still cold) and try to listen but there is no whistle unless i'm driving.

tzaracki14

Spray some starting fluid .. Brake parts cleaner .. Any combustible spray onto the intake manifold .. If you can feel/hear your idle change it's your intake/exhaust gasket ... It sounds like your vacuum leak might be too small for this to work .. But if you spray your gasket and your noise goes away ( this is what happened when I did it on my 2000 xj with same symptoms) you should still look to replace your intake gasket.. Fairly easy job

TheGreatGazoo

Does it sound like it is coming from the rear of the engine near the firewall?

JamromXJ

Before you jump into the intake/exhaust gasket... check the following for air leaks:
Throttle body gasket
Throttle body butterfly valve (clean and making full contact)
all vacuum hoses
fuel injectors - they have o-rings that can leak.
Try tightening the rear intake/exhaust manifold bolts (don't go crazy, if already tight, leave them alone)

Once those are good, move on to the intake gasket.

I just rid myself of the same issue. This is an extremely common problem.

I had replaced my exhaust header with a new APN, cleaned out the intake and painted it... then installed both onto a new Feltpro gasket, having cleaned and wire wheeled all surfaces to a near mirror finish...using copper RTV... proper torque pattern and settings.. etc.. etc.. per the Service Manual.. etc.. etc.

Put it all together (a few other new things as well) and ran it for a few days.

Low and behold.. it somehow f'n leaked and the teapot whistle syndrome started.

I took carb cleaner... (try to avoid using started fluid, the heat from the exhaust manifold could ignite it and cause a grease fire. The carb cleaner is less flammable. Get one with a nozzle tube so you can get acurate shots.) and sprayed it on each intake port. Listen for the RPM change. Once you hear the RPM drop, you have it.

Now the fix... one of two things. Replace the gasket. It's a easy but an involved job and will take a good part of a sunny day... and maybe more if you're not a tool guy.

Second option... get the copper based high heat RTV and a small screw driver. Start the Jeep and let it heat up (should already be hot considering that you were just spraying it with carb cleaner). Once it's hot... plug the hole by applying small amounts of RTV to your screwdriver and "grouting' in the the area of the hole. Usde your finger as well once the intake/head is cool enough. Don't glom it on, just try to pack the spot where the hole is. Before the RTV cures, jump back into the seat and run the engine for a few moments to pull in the RTV deeper into the problem spot. Don't rev the engine, just idle. This is a suction leak, so the goal is to bind the hole, and clog the suction with the RTV. If the hole is just a pinhole, this will work fine. Listen to hear if the whistle stopped, if it did. Shut the motor, and let it cure.

If this does not plug the hole, try a little more... if after it still whistles... back to option 1. That means you have a larger crack, split or pieces missing.

mikeybonz

thanks for the advice guys IT Sounds like it is coming from the front of engine, put i can't pinpoint while i'm driving the truck because it only happens while driving but goes away once the engine is warm and doesn't whistle at all if i'm in park or stopped at a light.

I wish it would make the whistle while i was in park and idle so that i could try these options, but it doesn't. The WHISTLE ONLY HAPPENS WHILE I'M DRIVING, IF I COME TO A STOP OR PUT TRUCK IN PARK I GET NO WHISTLE. And this whistle goes away once the truck is warm or close to 210 temp.


I don't mean to repeat myself but i'm just trying to state when the issue happens.

Have another issue with a knocking sound i've had for awhile and spend a ton of money on to fix but to no avail i will ask in a new thread

Jooman07

The same is happening to mine. Has it thrown a code yet?

I just haven't had the time to find out where it's coming from yet. But yeah, it only does it while I'm moving and above 1000 rpm. It doesn't happen all the time though. Mine threw a code and it said it was the leak detection something...in other words, vacuum leak somewhere. The noise doesn't need to be present for you to spray around the engine bay. Look where your vacuum lines are and spray around them. Once you here the idle drop..that's more than likely where your leak is.

mikeybonz

no haven't received a code yet.

its weird tho on days 40 degrees or above this sound/whistle will not happen as the engine gets warm. only on very cold days or anything less the 40 degress from what ive noticed

bring on the warm days!!

tlang

Problem solved! Its a summer jeep! haha just playin

Can you power brake it in drive to reproduce? (in drive, foot firmly on the brake, other foot brings up rpms to like 2k or something, not a burn out)

Just trying to see if we can find a different way to reproduce.

Does it happen under acceleration? Or only at a steady cruise?

Teephphah

Is the whistle constant, or does it change with more/less throttle or speed when you're moving?

DCXJ

I have this exact same problem in my 2001. Only at speed (1,500 RPM / 55 MPH) and only when it's around or below freezing outside. As soon as I speed up above 55 MPH or slow down below 50 MPH it changes pitch and goes away. Sounds like it's coming from the rear of the engine, almost right in front of me. And just painfully obnoxious.

mikeybonz

it for sure is a summer jeep but then again i gotta get the ac fixed

it is a constant sound that will only go away for good when the temp of the engine is warm

But like DCXJ HAS STATED if i'm driving 30mph i will hear it then i come to a red light and or stop sign and it goes away. then it will start up again when i start driving again.

i would basically say it takes about 8-10 min of driving then the whistle will finally go away until the truck gets cold again then same procedure.


i STATED something in my first post i believe i had a new thermostat put in and instead of the person using a gasket for thermostat they corked around it with that blue CORK.

Is it possible the whistle could be coming out from there. Like a small Hole in the Cork. I cant drive the truck like ACE VENTURA with my head out the window and hood up to really find out where its coming from.

but thank you guys for all the replies and help.

tlang

I doubt that the T stat has anything to do with it. If its not leaking then they essentially did the job correctly.

Wouldnt it be easier if we could drive like that! HAHA

DennisG

I've got the same thing happening with my 2000 XJ. See my thread below.....lots of good advice there.

https://www.cherokeeforum.com/f2/whi...r-hood-207111/

I'm finally going to tackle it today. I'll let you all know how it shakes out.