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Class A DP Fumes in Coach While Driving

janstey58
Explorer
Explorer
All, In 5K miles of operation this year, our DP has a strange issue that has only occurred three times in 10 months. We will get a strong diesel exhaust smell in our 2015 Fleetwood Discovery 40E. It will last about 15mins then go away. I also find a small amount of black soot on one small portion of the rear engine hatch. I have read there is a DEF regen cycle on this ISL9 Diesel engine, so I am guessing that is the source of the fumes. All windows/vents are shut tight, and our front air was set for recirculate. Has anyone else experienced this and how did you resolve. I read many people just put up with this? Thx!
Jeff and Kim
2015 Fleetwood Discovery 40E
Freightliner Chassis 380HP DP
2012 Ford Escape Limited Toad
21 REPLIES 21

janstey58
Explorer
Explorer
Funny we never get a CO alarm when this happens, that really makes me wonder?
Jeff and Kim
2015 Fleetwood Discovery 40E
Freightliner Chassis 380HP DP
2012 Ford Escape Limited Toad

xctraveler
Explorer
Explorer
I have not seen you report that you have a CO warning when this happens. That is a good thing. Have no experience with your specific failure. I suspect you know that if you get a CO warning, pull over and shut it down and evacuate while thinking about next steps.

We had a exhaust manifold seal fail on a gasser and we had CO in the coach. Opened all windows and kept moving as we were on a narrow mountain road with no shoulder or pullouts. The open windows cleared the CO For the remaining 15 minutes of our drive. If the alarm had continued for another 30 sec, we would have bailed where we were.
Paul
2012 Phaeton 36QSH on Freightliner Chassis with a Cummins 380 pushing it. 2011 Cherry Red Jeep Wrangler Rubicon with US Gear Unified Tow Brake System. Check out my blog
FMCA 352081 SKP# 99526

wildmanbaker
Explorer
Explorer
There is no pat answer, give it a try, it may be what it needed.
Wildmanbaker

janstey58
Explorer
Explorer
I have a turndown exhaust pipe that points downward. Should I tilt it outward toward the curb as I see on other DPs?
Jeff and Kim
2015 Fleetwood Discovery 40E
Freightliner Chassis 380HP DP
2012 Ford Escape Limited Toad

wildmanbaker
Explorer
Explorer
Do you have a turn-down on the exhaust? If you do, try rotating it toward the back of the MH and see if this helps. If you don't, consider getting one. The air flow thing.
Wildmanbaker

janstey58
Explorer
Explorer
The hatch seal is 2 years old and is tight. Also checked all exhaust fittings and all are in great shape and all tightly connected.
Jeff and Kim
2015 Fleetwood Discovery 40E
Freightliner Chassis 380HP DP
2012 Ford Escape Limited Toad

Sam_Spade
Explorer
Explorer
janstey58 wrote:
My air was on recirculate at the time.


"Recirculate" does NOT recycle 100% of the air. About 20% still comes in from outside......in an attempt to maintain a slight positive cabin pressure and prevent the exact thing that you are having a problem with.
'07 Damon Outlaw 3611
CanAm Spyder in the "trunk"

NEHOG
Explorer
Explorer
janstey58 wrote:
... I also find a small amount of black soot on one small portion of the rear engine hatch. ...


Were this mine, I'd certainly see if there is a damaged seal or seal surface. This is a giant red, unh, no, black flag waving here!
My name is Peter, and I'm never growing up.
(Holiday Rambler 40 DFD)

janstey58
Explorer
Explorer
My air was on recirculate at the time.
Jeff and Kim
2015 Fleetwood Discovery 40E
Freightliner Chassis 380HP DP
2012 Ford Escape Limited Toad

Sam_Spade
Explorer
Explorer
doxiemom11 wrote:
Don't know about the fumes, but with your setting on "fresh" - you are pulling outside air into your rig. If you set it on recirculate, it will use inside air only. Try not using the "fresh" setting and see if it still happens.


And to elaborate on that just a bit:
Under just the right conditions, the air currents around the body may "pull" the exhaust TO the point where the fresh air intake for the HVAC is located. I know it is hard to imagine this happening when you are cruising down the highway but it CAN and DOES happen sometimes.

In some cases, a slight modification to the exhaust exit will cure the problem......like an exhaust tip extension that directs the exhaust flow more toward the rear....and/or farther away from the body and under-carriage.
'07 Damon Outlaw 3611
CanAm Spyder in the "trunk"

doxiemom11
Explorer II
Explorer II
Don't know about the fumes, but with your setting on "fresh" - you are pulling outside air into your rig. If you set it on recirculate, it will use inside air only. Try not using the "fresh" setting and see if it still happens.

janstey58
Explorer
Explorer
I did check for any issues with the exhaust system and everything is tight, our DP is only 3 years old. Thanks for all of the input, I think I have a handle on this now.
Jeff and Kim
2015 Fleetwood Discovery 40E
Freightliner Chassis 380HP DP
2012 Ford Escape Limited Toad

Jim
Explorer
Explorer
I had a '94 Bounder Cummins 5.9 diesel mechanical engine that would do that on occasion. I also thought it was kinda weird. What I figured out was that it was (in my case) caused by strange wind patterns on the road. Certain speed wind, certain wind direction, and my RVs speed combined to push fumes back under the RV and allowed it to seep into the house.

This would happen mostly with the drivers window cracked. That would cause negative pressure in the cockpit drawing air from the back of the RV, and sometimes I'd get that smell. But it would only happen occasionally, maybe 10 times over 12 years of full timing, and would only last 15 or so minutes.

I'd ignore it after checking out other suggestions.
Jim@HiTek
Have shop, will travel!
Visit my travel & RV repair blog site. Subscribe for emailed updates.
Winnebago Journey, '02
Cat 330HP Diesel, 36.5', two slides.

Sam_Spade
Explorer
Explorer
Executive wrote:

P.S. Instead of asking "WHY", check for a leaky exhaust system.


+1

AND....an authorized service shop for that model of RV....or for the engine IN it, might be able to answer your question quickly and easily.

SOME of the gasses that can come in with the smell can be dangerous.
'07 Damon Outlaw 3611
CanAm Spyder in the "trunk"