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Exhaust Leak?

kdailey4315

kdailey4315

NAXJA Forum User
Location
Pacifica, CA
I recently finished an APN header and brown dog motor mount swap and now I'm getting a very loud exhaust noise in specific conditions. It doesn't have the tick noise that was there with my cracked stock manifold. It only makes the noise when the jeep is driving and accelerating. When I'm coasting its smooth as silk and purres like a kitten. The noise gets louder as the driving load gets higher. It will not make the noise when idling or if I rev it while idling. Any idea what it could be? I'll try to post a sound clip later tonight.
 
kdailey4315 said:
I recently finished an APN header and brown dog motor mount swap and now I'm getting a very loud exhaust noise in specific conditions. It doesn't have the tick noise that was there with my cracked stock manifold. It only makes the noise when the jeep is driving and accelerating. When I'm coasting its smooth as silk and purres like a kitten. The noise gets louder as the driving load gets higher. It will not make the noise when idling or if I rev it while idling. Any idea what it could be? I'll try to post a sound clip later tonight.
Click to expand...

If it only makes the noise while driving or accelerating, it sounds like the motor is torquing up on the driver side, and is moving the exhaust some were enough to cause a exhaust leak. Then when you let your foot off the skinny pedal, the motor quits torquing up, and the exhaust leak goes away because the motor has settled back down to its normal position. New motor mounts or not, i have noticed my 4.0 moves up and down a inch or two under a load. Maybe set you e brake, and let the clutch out a little giving it a little gas to put the motor under a load, and have a buddy listen to see if he can hear were the exhaust leak is coming from. If its a automatic, put the tranny in gear, and your foot on the brake giving it a little gas, and this should put enough torque on the motor to find the exhaust leak.
 
Judging from the video it sounds like an exhaust leak where the header meets the down pipe.

I doubt the engine moving theory causing the leak as you have Brown Dog motor mounts. Probably the leak is there and the little movement just makes it worse. Are you sure the mounts just aren't transmitting more noise? Another thing you can do is with the engine running put a rag over the tail pipe to block the exhaust. The leak will become more apparent and may even make a whistling sound.
 
Inspect your recent work, make sure manifolds are correctly installed and the manifold and donut gaskets are properly located and undamaged. Go back over all the manifold and exhaust pipe fasteners and check their torque.
 
Thanks for the replies. I retourqued the manifold bolts and I'm sure it's coming from where the header meets the exhaust. I'll have to recheck it this weekend. The little doughnut that game with the header is tapered. Does the tapered end go in the header or in the exhaust?
 
Talyn said:
Judging from the video it sounds like an exhaust leak where the header meets the down pipe.

I doubt the engine moving theory causing the leak as you have Brown Dog motor mounts. Probably the leak is there and the little movement just makes it worse. Are you sure the mounts just aren't transmitting more noise? Another thing you can do is with the engine running put a rag over the tail pipe to block the exhaust. The leak will become more apparent and may even make a whistling sound.
Click to expand...

I have the same motor mounts, AND THE MOTOR STILL MOVES REGARDLESS.... no motor mount is solid..... and gee...lets put a rag on a hot manifold so it catches the rag on fire.....:doh:
 
maddogs1965 said:
I have the same motor mounts, AND THE MOTOR STILL MOVES REGARDLESS.... no motor mount is solid.....
Click to expand...
Yes, it moves, but not enough to CAUSE a leak.
and gee...lets put a rag on a hot manifold so it catches the rag on fire.....:doh:
Click to expand...
Learn to read. I never said to put a rag on the manifold what the hell would that do? I said stuff a rag in the tail pipe to build up pressure in the exhaust system, which is a common procedure to help find an exhaust leak.
 
Talyn said:
Yes, it moves, but not enough to CAUSE a leak.
Learn to read. I never said to put a rag on the manifold what the hell would that do? I said stuff a rag in the tail pipe to build up pressure in the exhaust system, which is a common procedure to help find an exhaust leak.
Click to expand...
If the exhaust leak is under a load or driving like he explains, what does that tell ya? something is moving enough to cause the exhaust leak. He also stated there is no leak at idle or revving the motor......so once again its only under load, so something is moving, and gee what could that be THE MOTOR, its not ROCKET SCIENCE buddy!!!! :moon:
 
Just because the engine moves does not cause an exhaust leak. The leak is there by some other action, improper gasket install, lose bolts, bad gasket, etc. His new engine mounts are not the cause. Maybe he should just weld in some 1/4" steel plate for the engine mounts, a mid mount and weld the transmission mount up to. Thats got to stop the leak then.

Oh wait.. your the guy that can't even read a freaking manual (or the visor above your head) to figure out the difference between part time and full time on the transfer case. No wonder.
 
Talyn said:
Just because the engine moves does not cause an exhaust leak. The leak is there by some other action, improper gasket install, lose bolts, bad gasket, etc. His new engine mounts are not the cause. Maybe he should just weld in some 1/4" steel plate for the engine mounts, a mid mount and weld the transmission mount up to. Thats got to stop the leak then.

Oh wait.. your the guy that can't even read a freaking manual (or the visor above your head) to figure out the difference between part time and full time on the transfer case. No wonder.
Click to expand...

Maybe if it had a REAL T CASE in it, i wouldn't have to READ THE STUPID MANUAL, but then again that's a JEEP FOR YA!!! hasta and i have forgotten more about wrenching and wheeling than you have learned evidently you :looser:
 
Talyn said:
Just because the engine moves does not cause an exhaust leak. The leak is there by some other action, improper gasket install, lose bolts, bad gasket, etc. His new engine mounts are not the cause. Maybe he should just weld in some 1/4" steel plate for the engine mounts, a mid mount and weld the transmission mount up to. Thats got to stop the leak then.

Oh wait.. your the guy that can't even read a freaking manual (or the visor above your head) to figure out the difference between part time and full time on the transfer case. No wonder.
Click to expand...

Maybe if it had a REAL T CASE in it, i wouldn't have to READ THE STUPID MANUAL, but then again that's a JEEP FOR YA!!! hasta and i have probably forgotten more about wrenching and wheeling than you have learned evidently you :looser:
 
Talyn said:
Just because the engine moves does not cause an exhaust leak. The leak is there by some other action, improper gasket install, lose bolts, bad gasket, etc. His new engine mounts are not the cause. Maybe he should just weld in some 1/4" steel plate for the engine mounts, a mid mount and weld the transmission mount up to. Thats got to stop the leak then.

Oh wait.. your the guy that can't even read a freaking manual (or the visor above your head) to figure out the difference between part time and full time on the transfer case. No wonder.
Click to expand...

OH!!! and bye the way, too answer your stupid statement about not being able reading the sun visor or the manual about the T case,.....since this vehicle is over 21 years old there is no such thing as a owners manual in the glove box, and since i actually wheel my Jeep in the rocks, and its not a MALL CRAWLER unlike yours, i actually have a full cage roll bar inside the Jeep, so the sun visor does not drop down enough to be able to read the back side of it.....but I'm sure you will type something else to keep making your self look like the village IDIOT with out knowing the facts behind what your mouth is spouting out, just keep :hang: yourself :wave1:
 
Have you ever considered proofreading your posts? It could go a long way towards improving people's perception of your intelligence. By your screen name, I'd guess you are 46 years old, so you didn't grow up in the computer generation. Your grammatical skills should be better than what you're showing us. ;)
 
This thread got interesting. It looks like the bolts that connect the header to the exhaust had worked themselves loose. It started out only under load and then by the end of the week it was happening all the time. I tightened them back up and all is well. Will this continue to happen or was this just because it is new?
 
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