The worst type of exhaust leak... (1 Viewer)

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Jul 2, 2019
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Connecticut
Hi all. I’ve been living with an exhaust leak on my ‘94 for a while and it’s starting to drive me nuts. When the PO did the head gasket, he must’ve struggled to get the exhaust manifold off and left a nice gouge in the mating surface. Obviously the real fix would be to pull the head and weld, but I’m in no position to do that right now and few shops near me are even capable of welding aluminum. My dad suggested pulling the manifold, using some JB Weld ExtremeHeat or Muffler Cement to fill the fissure, and then sanding it flat once dry. Is that a horrible idea? Any suggestions will be more than appreciated. Manifold gasket and hardware is all pretty new.
 
Joined
Aug 8, 2018
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667
Location
Lake Waconia, MN
Hi all. I’ve been living with an exhaust leak on my ‘94 for a while and it’s starting to drive me nuts. When the PO did the head gasket, he must’ve struggled to get the exhaust manifold off and left a nice gouge in the mating surface. Obviously the real fix would be to pull the head and weld, but I’m in no position to do that right now and few shops near me are even capable of welding aluminum. My dad suggested pulling the manifold, using some JB Weld ExtremeHeat or Muffler Cement to fill the fissure, and then sanding it flat once dry. Is that a horrible idea? Any suggestions will be more than appreciated. Manifold gasket and hardware is all pretty new.
Pics!!!
 
Joined
Jul 2, 2019
Messages
51
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Connecticut
I forgot to take pics when I had the manifold off 😓😓

the gouge isn’t all that deep, but extends from the mating service just past it so air flow through and tick tick tick away. If I have time after undercoating the truck, I’ll sneak it off this weekend and take some pics
 

leonard_nemoy

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Jan 19, 2005
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1,781
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South west utah
Just get it fixed and dont ignore it. I was always told exhaust leaks in manifolds are bad if they are close to the block. If your leaking next to the block it can cause back pressure or somehow cause the heat to build up on the exhaust valve closest to the leak. This supposedly can lead to a burnt valve.

I had a 98 tacoma with a cracked manifold, I ignored it for 2 years and than I burned a valve. All of my valves were great except on the cylinder where the manifold was cracked. That is when I learned of this supposed phenomenon.
 
Joined
Feb 7, 2015
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668
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Eastern Washington
Welding cast aluminum is very difficult and frankly would probably make it worse. Better bet would be to braze fill the area.

I agree on fix it now. Not sure JB weld or any epoxy based material will hold up to the heat. Personally I'd go with something like this Alumiweld stuff if you're going to take it off to repair anyway and don't have access to regular brazing equipment. Oxy torch and some aluminum welding rod is all you need. Does not need to be pretty since you'll grind/sand it smooth anyway.

Aluminum repair kits, repair aluminum by welding with a Propane Torch - Alumiweld
 
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