Exhaust leak into coach

[Lucky duck]

So I have a 2005 coachman santara select 36 ft. I have the chevy 8.1l v8. My last trip out going up a grade my engine shifted into 2nd gear and I started getting exhaust into my coach, bad enough that it burned my eyes. So when I got home looked for exhaust leakes around manifolds and found non nor any soot. My pipe where it connects to the manifolds were loose so I changed the gaskets (donuts) . Today on my trip 150 miles of up and down grades and no problems then all of a sudden back to fumes. Any ideas?

[GG391]

Hey Lucky Duck,

If this happens while moving, I don't think it comes from the exhaust manifold or near the front of the RV as I would think there is somewhat enough air flow to blow any fumes away even if you are in 2nd gear. I would look at the rest of the exhaust system, tail pipes and where fumes could possibly get into the coach.

[Duner]

If you run with the roof vents open, that could create enough vacuum to suck exhaust in from just about any small opening. Any open windows and a wind coming from the right direction could also bring in exhaust.

[1972VWbus]

Crawl back under and check the donut gaskets again.


Did you replace the nuts & springs?

[Arch Hoagland]

Originally Posted by Duner

If you run with the roof vents open, that could create enough vacuum to suck exhaust in from just about any small opening. Any open windows and a wind coming from the right direction could also bring in exhaust.

We've found that to be very true. We keep all vents and windows closed tight while traveling.

[BikerGirl]

I had a similar exhaust smell last summer; replaced the original donuts and wala! no more leaks!

[David 70]

Check and make sure your donuts didn't burn out again. I replaced mine twice with parts store ones and finally got a set from Brazels and no problem since. I did replace the studs for the second time on the second set but used them again on he Brazel's set. They are spendy but if something works the cost is irrelevent.

[Fyrflie]

A trick I learned from you tube.
Plug your shop vac hose in to the exhaust port of the vacuum them take the open end of hose and stick it in your tail pipe. Tape it to form a seal. Turn on the vacuum then feel around each joint of the exhaust system.
If there is a leak, you will feel the air coming out.

I had a bad exhaust leak, both manifolds were warped and both donuts were compromised. There was no visual indication of a leak. Anywhere.

Using the air test, I was able to find and fix everything.

[fayjim2]

Fyrflie. Did you buy expensive original manifolds or put on headers??

[Fyrflie]

Originally Posted by fayjim2

Fyrflie. Did you buy expensive original manifolds or put on headers??

I unfortunately live in California so headers were not an option.
I had my original manifolds machined flat to fix the leak (warped surface).

[Lucky duck]

So I got the problem fixed. Where my tail pipe connected after the muffler was loose allowing massive amounts of exhaust to come out and build up under the coach. So I unbolted both of them cut the pipe flush got new tail pipes clamps and sealer and did all the work in a state park in northern Idaho. I'm sure they loved the noise but got it done. Drove the 500 miles home and no more issue. It's amazing what a small leak can do.

[Fyrflie]

Glad you found and fixed your leak.
And for posting your fix on this forum.

Happy travels

[dave6152]

Originally Posted by Fyrflie

A trick I learned from you tube.
Plug your shop vac hose in to the exhaust port of the vacuum them take the open end of hose and stick it in your tail pipe. Tape it to form a seal. Turn on the vacuum then feel around each joint of the exhaust system.
If there is a leak, you will feel the air coming out.

I had a bad exhaust leak, both manifolds were warped and both donuts were compromised. There was no visual indication of a leak. Anywhere.

Using the air test, I was able to find and fix everything.

excellent idea