Forum Discussion

janstey58's avatar
janstey58
Explorer
Nov 06, 2017

Class A DP Fumes in Coach While Driving

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!
Class A
  • janstey58's avatar
    janstey58
    Explorer
    Nov 14, 2017
    Funny we never get a CO alarm when this happens, that really makes me wonder?
  • xctraveler's avatar
    xctraveler
    Explorer
    Nov 13, 2017
    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.
  • janstey58's avatar
    janstey58
    Explorer
    Nov 10, 2017
    I have a turndown exhaust pipe that points downward. Should I tilt it outward toward the curb as I see on other DPs?
  • wildmanbaker's avatar
    wildmanbaker
    Explorer
    Nov 10, 2017
    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.
  • janstey58's avatar
    janstey58
    Explorer
    Nov 10, 2017
    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.
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Nov 09, 2017
    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.
  • NEHOG's avatar
    NEHOG
    Explorer
    Nov 09, 2017
    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!
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Nov 08, 2017
    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.

About Motorhome Group

38,707 PostsLatest Activity: Feb 19, 2025