fixing exhaust leak

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bcarli

Veteran Member
Joined
Aug 7, 2013
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84
Location
usa
Vessel Name
Pandion
Vessel Make
Nordhavn 46
I have an exhaust leak on my hino 135 turbo charged diesel. I have enclosed a few photos. There is no play where the exhaust flange bolts on and I'm not sure what happened to cause this gap. I think its to big of a gap for just a gasket failure. My question is it seems like an easy fix if I use some heat gasket silicone product

https://www.amazon.com/Permatex-811...gasket+sealer&qid=1567977198&s=gateway&sr=8-2


I think taking it apart and replacing with a gasket could open up a big can of worms. The gap at its widest in 3/16 and it is only open at the top of the flange.


Here are a few pics
thanks
 

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Are there bolts in each of the 4 corners of the exhaust flange? I believe that's what you're calling the upper part, underneath which is the gap you're asking about. It appears the bolts or fastening mechanism isn't holding the flange in place, or there's been warpage due to excessive heat, age, many temp/coolding cycles, etc., or the gasket has become deformed or missing material. I wouldn't recommend stuffing the cracks with a high temp sealant of some kind. Find out what is going on there, the root cause, and return it to as it was designed to be.

I have a similar connection from my exhaust outlet to the riser, and there's a metallic/fiber gasket between the two. The riser is held to the engine outlet with 4 sturdy bolts, one in each corner, with the gasket sandwiched between. I'd be concerned if my exhaust outlet/riser interface looked like yours. I think you should be too.

Good luck!
 
Looks like it REALLY overheated at that flange and warped.

David
 
A little more information is in order. Is this picture taken with all the other exhaust manifold bolts removed or at least loosened? It sounds like you are saying that 3/16" is the maximum gap on this one cylinder, with all other exhaust bolts still tightened? If so, you're right something else appears to be going on. Best fix is to totally remove exhaust manifold, inspect for cracks, face mating surfaces so that all are on the same plane (machine shop work), then reinstall with the correct gasket.

Using gasket sealer of any type would be just a stop gap measure (no pun intended) to get you to a place where the work would be convenient to accomplish . . . which it sounds like is where you are now . . . so a permanent fix is in order (see above).


Alternately, you could put in a thick exhaust rated gasket, seal with gasket sealer on both sides, torque to correct specs, and hope for the best . . .
 
djmarchand said:
Looks like it REALLY overheated at that flange and warped.

David
Click to expand...




Bingo! I would remove the exhaust and check the turbo, or take the turbo off and have it serviced. Do you have an exhaust gas temp gauge? The only time I have seen exhaust open up like that on a diesel was after being run under load for to long and having high EGTs for an extended period.
 
slowgoesit said:
A little more information is in order. Is this picture taken with all the other exhaust manifold bolts removed or at least loosened? It sounds like you are saying that 3/16" is the maximum gap on this one cylinder, with all other exhaust bolts still tightened? If so, you're right something else appears to be going on. Best fix is to totally remove exhaust manifold, inspect for cracks, face mating surfaces so that all are on the same plane (machine shop work), then reinstall with the correct gasket.

Using gasket sealer of any type would be just a stop gap measure (no pun intended) to get you to a place where the work would be convenient to accomplish . . . which it sounds like is where you are now . . . so a permanent fix is in order (see above).


Alternately, you could put in a thick exhaust rated gasket, seal with gasket sealer on both sides, torque to correct specs, and hope for the best . . .
Click to expand...
That is the turbo to manifold flange. Not the manifold to head flange.
 
Where are the flange bolts...? What am I missing?

This looks like a serious overheating issue to me. When and how was this discovered?
 
Not sure why you are hesitant to take it apart and sort it out properly. These are service items and should be disassembled checked with a 3-6 year interval (depending on salt/fresh, running time hours, etc).
 
Permatex Suggested Applications: " Valve covers, oil pans, timing covers, water pumps, thermostat housings, transmission pans" don`t include this.
Best take it off and see if the flange can be made flat again.
 
Permatex sealers only work where you have a close fit. The temps in that area could be Well above the intermittent 650° temperature on the packaging. At WOT the temp will be above 650°. I doubt the sealer will last 10 minutes.
In the pictures it appears to have been leaking for a long time. You need to take it apart and reassemble with a new gasket.






 

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Surely the mounting studs have broken off. Take it apart and fix it.
 
Xsbank said:
Surely the mounting studs have broken off. Take it apart and fix it.
Click to expand...


Agreed. I think I see a broken off stud in one of the pictures. But I think you will also find a warped exhaust pipe flange. And hopefully not a warped turbo flange. I think you will need a new exhaust pipe flange and maybe some length of the attached pipe. It will probably have to be fabricated, but done all the time in marine exhaust.


I've used the red permatex to help seal up a turbo to manifold gasket before. It works great, but isn't meant to really fill a gap, just to better seal to surfaces that already mate well. I think it would blow out of your 3/16" gap is very short order.
 
Thank you all for your feedback. I will take it apart and get it fixed..Living on San Juan island (Washington State) makes everything harder...If anybody could recommend a good fabricating company in my areaI would appreciate it.
 
It's nice when a boat owner takes the advice of this forum. "Gubbering" it up wouldn't get him out of the harbor. It needs to come apart and be fixed properly. I agree with the group, something got very hot ! I would guess the metal has also become fatigued, replace the components, they are cheap compared to the alternatives

pete
 
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