Do I have an intake manifold leak?

[joniki]

Hello, how is your Jeep looking in 2023? Any whining noises since then? Facing similar issue.

I had a similar noise on my 06 4.0. I had an intake manifold leak I found with a cheap mechanics stethoscope I picked up from HF.

 

[LuckyTJ]

Thx. I am looking at Mopar for parts replacement, i have both the intake manifold and the pulleys YT saved and the pulley replacement is definitely much easier ha. One thing i’m confused about is why does the engine need to warm up before that sound starts and why is it based so much on how you push the pedal? What do pulleys have to do with this? Who knows. Thx for the update though!

I've read here in the forum that for these parts Mopar is the way to go as well. Good luck on your repair. I love the little TJ, but it definitely makes plenty of noises- engine bay, suspension, etc. It's not exactly a precision build it seems, and you'd never say it "purrs like a kitten"... LOL

 

[JamesBCPA]

So, I've had similar sound for over a year. One reason or another kept me from getting it to the shop and of course there were times I took it and it didn't make the sound. Most recently, the sound never stops. Mechanic changed throttle body about 2 months ago with no change. Took it back yesterday and he believes it is a vacuum leak at the intake manifold. Mine is a 2000 TJ with 250,k miles on it. His suggestion is to replace the intake manifold with a new one. Not much difference in the cost of a new one and used one since the primary cost in such a job is labor. Also, replacing gaskets would be almost as expensive as used manifold - again, labor. Any thoughts? We haven't made a final decision, since no one has a new in stock, right now. By the way, I'm not the guy to do this myself.

 

[macleanflood]

Mechanic needs to smoke test the intake before you throw more parts at it.

-Mac

 

[JamesBCPA]

Mechanic needs to smoke test the intake before you throw more parts at it.

-Mac

He actually did that to determine where the leak was.

 

[macleanflood]

Just saying there's a big difference in these two statements ...believing there's a leak in the intake and the mechanic performed a smoke test and determined the intake is leaking.

Where was the smoke coming out? Does it need a new gasket? Lots of fittings and caps? Is it cracked?

I bought a smoke machine on Amazon for $30 to run my own tests.

My guess is you didn't need the throttle body either...I can link a YouTube video if you want on how to install O-rings. Mine was leaking through the gasket.

-Mac