Exhaust manifold gasket leaky

[Rawze]

(10-27-2023 )Punchy Wrote:  Interesting thing I see on this busted gasket between the turbo and the pipe section with the DPF doser and NOx sensor. I didn't notice until a passersby pointed it out. The broken part that looks like a donut with a bite in it. There is actually a guide hole that lines up with the pipe section. (Red arrow) A small bump is there in the pipe that'll go through the gaskets hole. I didn't see that because the "donut bite" is there widening the guide hole. You see the new bump I made when I removed the pipe previously and reinstalled (Yellow arrow).

some gaskets have a hole for an alignment dimple in the doser pipe flange. Maybe someone installed the gasket incorrectly?.

[Punchy]

Rawze ' Wrote:  some gaskets have a hole for an alignment dimple in the doser pipe flange. Maybe someone installed the gasket incorrectly?.

I think I am the one who was incorrect and made that dimple. Attached is a pic of the new gasket with the little alignment knob hole. The old one's injury is covering up it's own alignment hole.

Also have attached the little accordion section coming off the manifold. On the left there, as I'm about to retighten the clamps, seems the gap is too wide for the clamp? Did I drop or misplace a gasket? EDIT it is in backwards. I'll leave this gaffe here so the point of paying close attention is made.

[Punchy]

When I put everything back together, I can still hear a leak at the manifold. The exhaust is rising up again, can't quite tell from where because I'm outside and yesterday was particularly windy. I let it run about 45 minutes as I refilled the coolant and the hissing and smoking remained. Drove it about five miles and the truck is noticeably more responsive with more get up and go. But when I slowed to under ten mph and/or stopped for a light the hissing came back like before the repair.

To get ahead of two questions I would ask: I've triple- and quadruple-checked my connections and the torque is at 44.

I talked to an OO who's done many repairs on his own truck. He said the first time he did the manifold gaskets, the same thing happened to him, and he was told that the gaskets would seat themselves after driving a bit (not sure how long but sounds like an hour or two). And he said, that was true and everything was okay after that. He also mentioned a term "turbo slobber" where the turbocharger might seep a bit of oil after the repair, before sealing up.

Headed back to the lot to check behind myself again.

[tree98]

(10-31-2023 )Punchy Wrote:  I talked to an OO who's done many repairs on his own truck. He said the first time he did the manifold gaskets, the same thing happened to him, and he was told that the gaskets would seat themselves after driving a bit (not sure how long but sounds like an hour or two). And he said, that was true and everything was okay after that. He also mentioned a term "turbo slobber" where the turbocharger might seep a bit of oil after the repair, before sealing up.

Disregard all of that, none of that makes a bit of sense whatsoever.

If it's still leaking, you need to figure out EXACTLY where it's leaking from. If it's not obvious too the naked eye, you'll need to pressurize the entire engine by blocking off exhaust side of turbo and pressurize the other side of the turbo with about 30 psi of shop air.

[Punchy]

So. Looks like I put it back together properly. The hissing is elsewhere, upon closer inspection. There's ANOTHER leak, in the small section of hose that leads into the EGR valve. Seems that the smaller fuel hose leading down to the DPF doser, the hard metal part just before the flexible metal part, has been rubbing that EGR-linked hose and caused a tiny rip. "Plain hose" as labeled by Cummins.

This could have been the issue the whole time for all I know. Ah, well. If so, at least the manifold is updated and good for a little while. I hope.

Not only that: The turbo is leaking coolant on the block side. O-ring. I was very careful handling the turbo with removal and reinstallation but could be I dislodged something. So, gonna drain the coolant once more to replace the two connections back there. I think only one is leaking but why not refit both?

[Rawze]

Also make sure your exhaust is not clogged up. A plugged/blocked exhaust system will cause all kinds of issues with leaks and gaskets going out.