2003 Monaco Executive engine exhaust pipe

[Okiewebb]

We have our 2003 Executive in the shop to work on turbo air charge leak. Mechanic thinks our engine exhaust line is possibly the problem because it looks flattened. What should the exhaust line/pipe look like? Rounded or flattened on the bottom?

[timaz996]

What engine do you have? Pictures would also help.

[cbr046]

I'll ask the obvious . . . . how flat is it?

If the exhaust was flattened maybe, but IMO I don't think so.  But then I'm not a turbo expert. 

- bob

[Okiewebb]

Engine is Cummins M11 ISM

[vito.a]

The exhaust pipe on these coaches exits the turbo and runs down the drivers side and then goes under the engine oil pan to the passenger side rear corner.   Usually the trailer hitch cross member protects the exhaust pipe but it is possible to scrape it.  

Raise the coach up manually (engine running for air pressure) using the HWH air ride panel on the drivers left side.  Then go look under the rear and see if the pipe is smashed.  

[Chargerman]

The pipe that goes under the oil pan was flattened from the factory in many cases. Mine was on my 06 Exec. When I replaced it I used round pipe and it is still slightly above the protective crossmember. If your pipe looks like it has a uniform flat but otherwise is in good shape then it does not need replacing 

Edited April 11, 2024 by Chargerman

[Ivan K]

If it really is badly flattened, like by dropping the coach over a concrete block at some campground back-in sites, probably easiest repair would be a flexible piece like used on ours. But it is a 5" pipe, a little flatness won't make huge difference.

[Paul J A]

The shape may be distorted, but the cfm of exhaust is not disturbed until a bend, curve, in the straight line of it occurs. Go straight pipe and eliminate all back pressure. 

[Chargerman]

This is mine after I finished the complete replacement

[Okiewebb]

Thank you all for replying to our questions. My husband says that line is going to be replaced. We must have damaged it last summer on our wonderful CA highways……

[Chargerman]

If you are needing to replace that cross pipe I would suggest you take a real close look at the area that’s after the turbo. In many cases that is the first area to fail. Usually starts with small pin holes  

[Okiewebb]

Thanks for the tip. Will pass information on to my husband and repair shop.