fixed it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
so i bought some break cleaner and figured i spray a dab around the intake manifold with the engine running, sure enough the very last bolt closest to the firewall was loose.. it was actually about to fall out. i got it back in and snugged it and now the whistle is healed. thank god i was about to shoot the jeep lol

 

UNBELIEVABLE.... I had been living with that awful whistle for almost a year now!!!! I had been told by 2 mechanics that they couldn't find any leaks and everything was normal, and told by a 3rd that I had a cracked head, cracked exhaust or intake manifold, bad gasket, etc. Tightened up that last bolt and the whistle is gone!

 

Thank you sooooooo much!!!! I had that annoying whistle noise, and I tried everything. I was about to do the intake gasket when I came across your thread.


I last two blots were loose next to the firewall!!! no wonder, everyone says to change out the intake gasket, because that will fix the problem, only because when you put the new gasket on the bolts get tightened correctly...

 

Man I'm gonna have to check this now cause mine is doing the EXACT same thing. Glad I found this. So it was the last bolt on the intake manifold that was loose? Mine only does it intermittently though. But what you described is what mine does to the T.

 

That's how mine started, intermittently, it would conveniently stop after I would fix a new vacuum leak or clean/replace gasket on the TB or replace a cracked check valve... Drove me Nucking Futs!

Yes, the two bolts in the very back of the firewall (two different size bolts). The ones on each end are 15mm nuts, the ones in the middle are 14mm bolts. At least on my 2000 XJ...

I wonder, it the leaky valve cover (always start leaking in the back) is related too, by mere hard to reach location in the back....?

Good luck.

 

Yeah I have a leak somewhere coming from that area, I'll have to take a look when the weather clears up some. Even in the garage it's still pretty daggum cold.

 

Mine does the same thing Driftunit's did. Only difference is mine healed itself in the spring and now that it has become cold again it is doing it again. I will take a look at those bolts when I go home for Thanksgiving.