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Likely exhaust leak locations

I'm assuming I should see soot buildup where the leak would be correct? At least that's how I've been going about this phantom leaky business.

I am half tempted to pull the downpipe and fire the truck to just rule out anything post turbo (already pretty darn sure its pre turbo but the only leak I see is post turbo)
 
while you are there i would check the up pipe on the rt side looks like the flange weld cracked in side the flange on top. there shouldn't be any oil around where the up pipe meet the flange for the gasket.
 
That's exactly what I equate this sound to, and the exact part I don't want to replace, mainly due to cost. With emissions tests here I have to keep the EGR. And of course that OEM rt side up pipe is twice as much as the aftermarket EGR delete one... :banghead:

I'll take another look at the back side of that up pipe today. It's the only area in the whole exhaust I can see that could be leaking. I wonder if I could find something temporary to wrap around that area and see if the sound muffles, just to have a definitive answer.
 
If it is an expensive part, what about having it welded.
Wouldn’t know until you can see it how bad it would be to weld.

If that is a possibility, things like ib weld would be bad. What about packing the area with material like exhaust wrap?
 
Oddly enough, just picked up some exhaust wrap for my old ATC's header pipes. The DG pipes are great but have no heat shield on them. I'll spare a few feet for the up pipe and see where I get.
 
Just an update for those of you following.
I took it to a friend's shop and had him take a look at it. He found a crack/hole in the 1 year old downpipe. I have to pull it and pull the wrap off to see what I'm up against but he assured me that's the source of the leak. From what he could tell its in the middle of the pipe and the leak is pointed at the back of the block The newest piece of the whole exhaust system and its leaking... At least its easy and cheap. Will post pictures when I tear it apart.
 
Good find but weird. lol

Is it hard to pull down pipe? Looks real
tight up there. Not much room for arms, hands, or tools.

Getting the original dp out is a royal pain. You have to pull the turbo heat shield (cut mine in half and threw it away) then remove the dp heat shield and bend it all to hell to get it out. Also helps to loosen/remove the trans dipstick brace bolts. Finally you're to removing the dp and its a major struggle of wiggling, prying and pulling. All said and done it was 1.5 hours to get the old dp out.

Best part, the new dp was in and bolted down in less than 10 minutes. Figure that one out.

All that said I expect to undo the vbands on the dp and have it pull itself out from its home...
 
An LB7 downpipe is an improvement over a stock LBZ pipe and much better quality than the aftermarket units that crack... Or so I hear anyway

Btfarm, are you referring to the pass side up pipe? You can google search LBZ up pipe and be hard pressed to find the stock one with the egr riser. Even searching for EOM or STOCK and you get the LB7 variant which, I am not opposed to but due to emissions standards where I am I have to have it all in and reporting ready. And of course the LB7 set is a couple hundred dollars cheaper...

On to the bad news, pulled the dp and unwrapped it. There was a decent sized soot mark on part of the wrap so I figured that's where my buddy suspected the crack. NO CRACK :banghead::banghead::banghead:. So I am back to suspecting the up pipe again. I took some pictures of the up pipes with my phone but as of yet nothing is for sure telling me where the leak is. I'll try again after work with some light and hopefully pinpoint this thing.
 
One last update to this post.

I took the truck to a local but reputable diesel shop. They spent 3 hours going over the thing and claimed to have fixed my issue. Loose egr/up pipe bolts. Went to pay and pick up the truck and wouldn't you know it, the damn thing still ticks. They cut their bill in half, so $65 and still no fix for the truck. I have been thinking about one day doing the PPE manifolds and up pipes. Their suggestion, do the PPE up pipes and manifolds and you'll find the source of the leak then...Easy for them to say. :meh:
 
One last update to this post.

I took the truck to a local but reputable diesel shop. They spent 3 hours going over the thing and claimed to have fixed my issue. Loose egr/up pipe bolts. Went to pay and pick up the truck and wouldn't you know it, the damn thing still ticks. They cut their bill in half, so $65 and still no fix for the truck. I have been thinking about one day doing the PPE manifolds and up pipes. Their suggestion, do the PPE up pipes and manifolds and you'll find the source of the leak then...Easy for them to say. :meh:


Good luck to you I hate an exhaust leak.
 
Reviving this thread to give an update for those interested.

I took my truck to another mechanic that maintains a fleet of duramax trucks. He is pretty convinced that I have a lifter tick problem. Going to pick up the truck from him and discuss my options. I'm really hoping this isn't the case since it's not exactly a cheap fix.

If it is a lifter, I am thinking I might drop the coin to have him do head studs and PPE manifolds and uppipes since half will be torn down anyways and I'll save a little on labor.

Anyone done manifolds and up pipes and have any feedback? Is it worth the expense or no?
 
For those of you still interested in this train wreck of a thread.

Finally, after having 4 different shops look into the truck the issue has been found. Head gasket leak on cylinder #8, hiding behind the pass side up pipe.

Quote from a friend who manages a shop is $3500 plus parts (Gaskets, head studs, flow pro manifolds and up pipes). In total about $5200 provided the head and block look alright when its torn down. Gotta love working on these diesels. :dead:
 
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