Black marks on the ceiling and in the cupboards of a rear engine diesel motorhome

[edggy]

We have found that we are getting more black marks on the corners of our ceiling and in the cupboards of our motorhome the last year. Our motorhome is a rear diesel engine under the bed. When I removed the mattress cover to wash it, the side closest to the head of the bed was discoloured as well. We have a large mirror instead of a headboard. Would this be soot from the engine or mould? We are also starting to get a bit in the front of the cab as well. Any suggestions would be greatly appreciated, especially if you know how to clean up the discolouration. Our rig is a 1992 Europremier. 5.9 Cummins 230 hp. Any help will be appreciated. We have been living in this rig all winter in s california and use it all year round

[Gary RVRoamer]

From your description it sounds [to me] more like mold. Soot will smear easily, while mold usually does not.

Mold, especially in the ceiling, suggests dampness, which might indicate a roof leak.

[J Walker]

You probably would have smelled the exhaust if it were getting into the bedroom. But it would be wise to make some checks. Do you have a carbon monoxide detector in the bedroom? If not you should get one ASAP. If you have a detector and it shows little or no CO that is good. I would get under your MH and inspect the muffler and exhaust pipes. Any of the connections could be leaking.

[ChiefJohn]

Quote:

Originally Posted by RV Roamer [Gary] From your description it sounds [to me] more like mold. Soot will smear easily, while mold usually does not. Mold, especially in the ceiling, suggests dampness, which might indicate a roof leak.

Ditto Gary -- sounds like you have a moisture/mold problem. First, you need to find the source of the moisture and then treat the areas where the mold has found a home. As Gary stated, this could be an indicator of a much larger problem--immediate attention may mean $$$ in your pocket.

[AFChap]

We also have a mysterious black mark/smudge in one place on the driver's side rear of our coach ...a black mark on the ceiling at a right angle to the wall running apx 4-6" inward from the wall. I first noticed it over 2 years ago, and have watched it since. It has not grown or changed in any way. It looks like dark dust, but doesn't brush off to any extent. Our mark is nowhere near anything on the roof or side that could cause a leak, nor is there any evidence of any moisture damage. The only relationship of the mark to anything I can see is that it is directly in line with the center of a 120v outlet on the wall about 20" below the ceiling. I don't recall ever having used that outlet (on a shelf above the washer/dryer and in front of the upper cabinet where the washer water and power connections are and where we store detergents. We normally don't even see the mark as the DW keeps a couple of spare bed pillows there and they cover that area of the wall and ceiling...

Hmmmm ...just had a thought ...I don't recall whether or not the mark was there before we suffered damage from a lightning strike on an RV park electrical system a couple of years ago. The power cord end was melted, and transfer switch and hardwired SurgeGuard were fried in the electrical bay directly below that area ...there was other electrical damage also. Perhaps the mark is a "reflection" of the structural aluminum that was "energized" when the lightning hit...

[bldrbob]

I have some black marks showing up in the ceiling.I think they were caused by exhaust leaks cause when I checked the muffler had some large holes.The ceiling is formed foam panels with chases molded in.I think the rear cap was routing the fumes up into these chases or channels and coming out in the seams and around the light fixtures.
BOB

[deandec]

We have cleaned some soot marks with oxy cleaner in solution, sprayed on ceiling, and sponged off.

The engine compartment may need to be resealed with some "Great Stuff" or similar.

[Pairajays]

I think it is exhaust soot from the diesel engine. Looking at 10 to 15 year old coaches, with rear diesel engines, you will most likely see black soot on the overhead lining especially in the bedroom. This accumulates over many years and presents no danger of CO to passengers.

Jim

[Craig P.]

I've had ceiling marks on my last two MH's. My old MH was a front engine gasser Winnebago Adventurer. I would get black marks on the ceiling material at the very rear of the coach. They were straight black lines about 3 inches in length, right where the ceiling met the rear wall.

On my current coach, a diesel pusher, I get the same exact marks at the FRONT of the coach, directly over the driver and passenger seats. In both MH's the marks can be removed by cleaning with "Voom" spray cleaner, but they re-appear with time.

Total mystery to me...

Craig

[mickey53usa]

This is interesting as I have the same kind of marks as described by AFChap. I have four - two on each side of the bed, extending out from the wall about 4 inches. They are in a straight line with each other. The rear most ones are about 3 inches forward of the closet cabinet which is over the head of the bed. The next set is about at the end of the bed. Been there for the four years I have owned the coach. No moisture, just dark lines. Would like to have an explanation - looks like I found a way to clean them in this thread.
Rear engine diesel.

[John Wayne]

I have the straight marks on the ceiling also I think it is where the ceiling panels meet under the ceiling fabric and rub together making dust or dirt that bleeds through the fabric.

[RJay]

I had black marks on the carpet type ceiling on my Itasca Suncruiser which is a gas unit. Here is my theory.

Most of the black marks occur in Itasca/Winnebago motorhomes but more specifically to the particular roof design. The roof fiberglass curves around the edge of the roof and terminates in a channel. The fiberglass is not sealed in the channel but just lays there. It's held in place by the tension of the fiberglass and the front and back end caps. The channel has weep holes to allow water to drain. If you have ever turned on a vent fan before opening another window/door the air will be sucked in from under the roof and enter the coach through whatever opening(small) is available at the wall/ceiling joint. It doesn't have to be a vent fan that causes it to happen, I just use it as an example, a wind hitting the side of the coach could also be a cause. The point is the roof is not sealed and air can freely enter under the roof. It's only a theory but seeing some of the posters here have Itasca/Winnebago products I'm beginning to think there might be something to it.