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2001 4.0 sounds like a tea kettle in cold temps

Me thinks a vacuum line along the firewall/battery area?
 
My father used to seal up the fixin's for a big dinner in foil and place them around the engine compartment on the 4 hour drive up to the cottage. When we got there, the roast and all the sides were ready to eat. I don't think he ever tried putting a tea kettle under the hood though. Could be a boiling pot of screaming lobsters?
 
It's been a while since I've posted here. My 2001 Limited with 110,000 miles had made a tea kettle sound as well. This year it has gotten far worse. Here's what mine is doing.

On cold days only, the Jeep starts up fine. After about 3 or 4 minutes the tea kettle sound will begin. The pitch can be varied with very slight changes in the throttle. It is very loud but will go away when the vehicle warms up. Today I went to see if I could identify the noise. While whistling, I removed each vacuum line on the manifold (total of 4, 3 on the side of the manifold and the EGR on the top). I noticed NO difference in the sound while removing the lines. The brake boost line was replaced and is held on with hose clamps. I am at a loss where this is coming from also. Additional thoughts?
 
nylyon said:
The pitch can be varied with very slight changes in the throttle. It is very loud but will go away when the vehicle warms up.
Click to expand...

Two thoughts: either or both the the throttle body gasket or the airbox-to-throttle-body intake hose has a crack. Had a similar noise a few months ago after replacing the injectors and it turned out to have been both.

If it is the gasket, I would strongly recommend getting it from the dealer. It only runs a buck or so more than the parts store equivalent, but (in my case) had more surface area and was made of thicker material. Autozone's finest was flimsy and failed cure the problem.

Additional thoughts?
Click to expand...

Spray some starting fluid around the intake manifold with the engine running and see if the revs change; you could also potentially have a leak there.
 
Sure sounds like a vacuum leak.

Rather than hose it all down with starting fluid I prefer an unlit propane torch, less mess, same results.
 
87manche said:
Rather than hose it all down with starting fluid I prefer an unlit propane torch, less mess, same results.
Click to expand...

That's a damn good idea; dunno why I never thought of it myself. Thanks :)
 
I just removed the intake hose and looked down into the throttle body. It was FILTHY! I cleaned it out with cleaner, and I don't know about the noise (the engine is warm now) but it idles much nicer now too.

I think that I'll get the throttle body gasket anyway. After seeing what I can clean, I think that I want to take the TB off and give it a good cleaning anyway. Now to let the car cool down so I can test some more. (Keeping the can of carb cleaner handy when the noise comes back) Thanks guys! Now to search for the rear seat squeak fix....

Just got 4 new Michelins, time to fix some things...
 
Take off the belt start it up if no sound then you have a starting point that it not any thing belt driven.If you dont have a sound with belt removed turn each unit till you feel some thing tight or ruff felling. Check your alternator mine made a noise bad bearing when cold changed pitch and then stoped.After you know its not a belt driven noise then get some carb spray and go over your hoses and fitting listen for the sound to change or RPM to change.
 
After you clean the throttle body and replace the TB gasket, if the noise is still there try putting a little wheel bearing grease on the ends of the throttle plate shaft where it exits the TB--a slight leak in that area can cause a high pitch noise.

FYI--last year for the EGR--Exhaust Gas Recirculation--on the 4.0 was 1990. On the valve cover is the CCV--Crank Case Ventilation--like a PCV system only with a metered orifice rather than a valve. The front grommet on the VC is the filtered fresh air intake. The rear has the metered orifice and is connected to the vacuum port on the intake manifold.
 
joe_peters said:
After you clean the throttle body and replace the TB gasket, if the noise is still there try putting a little wheel bearing grease on the ends of the throttle plate shaft where it exits the TB--a slight leak in that area can cause a high pitch noise.

FYI--last year for the EGR--Exhaust Gas Recirculation--on the 4.0 was 1990. On the valve cover is the CCV--Crank Case Ventilation--like a PCV system only with a metered orifice rather than a valve. The front grommet on the VC is the filtered fresh air intake. The rear has the metered orifice and is connected to the vacuum port on the intake manifold.
Click to expand...

Great idea. During the week, I'll make my way to a Jeep Dealer and get the gasket then clean the TB. I guess that I've been working on my 6.0 Powerstroke too much and have EGR on the brain, thanks for the clarification, I know this isn't an EGR valve, just too much Ford on the brain!
 
Even after the TB cleaning, disconnect of the belt the whistle is still there. From the process of elimination, the only thing left is the intake gasket. Searching through youtube, I found a 2003 WJ that has the EXACT same whistle, http://www.youtube.com/watch?v=Y5_m6LRqkAw I hope that the original poster checks in to see if their whistle is the same as this. I think that I'm going to replace the intake gasket and see where that leads. It doesn't seem like a big deal, just the old rusty bolts and the bolts underneath. Anyone have a good writeup on removal to save some knuckles?
 
You might try just retorqueing the bolts. They come loose. I'd certainly try that before I went all in and took it off.
 
it's usually the ones on the bottom, by the exhuast manifold. I thikn the heat cycle works them loose.

Of course those are the most fun to get at.
 
nylyon said:
Searching through youtube, I found a 2003 WJ that has the EXACT same whistle, http://www.youtube.com/watch?v=Y5_m6LRqkAw I hope that the original poster checks in to see if their whistle is the same as this.
Click to expand...

Its not quite the same as my tea kettle...mine NEVER does it at idle. Its actually gotten to the point where the noise is there all the time, even when it's warm outside. So, at this point, i'm just waiting for something to break because i'm tired of screwing with it.

Pedestrians stare as i drive by, but i just pretend i'm making some good tea...
 
I felt the need to revive this thread...

With cold temps upon us, the tea kettle is back. However, I've noticed that it only makes the noise at speed and never while stationary and revving the engine. Also, if i drop it into neutral from drive, the noise stops for a very brief second. So, i'm thinking transmission at this point but this is where i'm stumped...but i think that rules out wheel bearings.

Hopefully someone can offer some more help...thanks!
 
I guess i'm ignorant, but what role might the belt play in this? I battled belt squeal years ago when i bought my Jeep so i'm familiar with the noise, and this is definitely not it.

Are there any vacuum lines or other lines i might check that run to/from the transmission?
 
The transmission has no vacuum lines but there are lines going to the charcoal canister in front of the fuel tank.

Do you have a CAI, throttle body spacer, or bored throttle body?
 
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