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What’s causing that diesel smell?
Ok, interesting question time. About a year ago, got this 2001 H3-45 Marathon. We put a decent amount of miles on it, averaging about 20,000 miles this year so now at 150,000 miles.
After the first trip, first wife says that she smells diesel. Humm, maybe the Webasto says the shop? Needed service anyway so did that. No change in the smell.
Then the shop guys figured out that the gasket on top of the fuel tank opening was installed catawhompus and had allowed some diesel to slosh up and pool on top of the tank. They replaced the gasket, steam cleaned off the top of the tank, replaced some of the damaged insulation and proclaimed it fixed.
A year later and first wife still complaining about diesel smell. She claims that clothes taken out after week long trip still smell like diesel, etc. I of course catch a whiff when opening the bus after a week closed up, but my sniffer is not even in the same catagory as hers.
So: Do 12 year old coaches just smell like diesel all the time? We recently had the carpets cleaned and that didn’t change her opinion. Anything anyone has seen what would cause this problem? Should I invest heavily in Febreeze? Change out the carpets to wood? Cover up with other bad smells? Too expensive to replace first wife, so looking for a solution.
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14 Replies
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No diesel smell at all in our ’99 with 160kmiles. But a little bit of diesel will go a long way. I’d double/triple check the fill hoses on both sides. Or just replace them to be certain.
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Charlie,
I would check the overflow tube at each fuel fill compartment. can get blocked with dirt, bugs, bee’s etc. Blow air down through the tube or pour in some water, it should run right out under the bus. You’ll see the overflow tube, just look in the fuel door compartment and look for a hole.
The other sources assuming your fuel tank vent is good, would be the Webasto or Generator fuel hoses. Sometimes fuel lines will permeate and it doesn’t take much diesel to stink up the bus. I had a smell in mine and found that if I fuel and get the dreaded burp, I’ll get some smell then from the OTR vents in the bus until the fuel dries, then it’s gone.
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we had a diesel smell. Some way something somehow went by the engine oil filters making over an inch long hole in the side of the muffler. It was not possible to see the hole unless the cover under the filters was removed. Had the hole gas welded closed and smell went away.
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Charlie,
Do you have slides? I have my reasons for asking:)
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Check the generator compartment for leaks.
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Yes, have two slides on this model.
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Check the bottom of the salon slide for any signs of looseness in the metal covering. We had a slight leak in that area on our coach and since repair our “diesel smell” has completely disappeared.
My speculation is that air was being drawn across the generator compartment and dragging some diesel smell with it.
Might be worth checking.
And by the way, the wife noticed the smell when I couldn’t sniff it at all!
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Do you have a roof generator exhaust? Exhaust pipes run through coach living area and, of course, there are entry and exit holes.
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Is the problem diesel exhaust odor or the odor of diesel fuel. Two different things and I am not clear on which smell is the problem?
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good question. It’s diesel fuel smell.
Thanks for all the ideas. I’m going to start working through the list.
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Diesel fuel smell can be the result of fuel leaking, fuel that once leaked but has now stopped but hasn’t been cleaned up, or a venting issue.
I would start at the beginning, meaning look at the filler ports and make sure if there is any residual fuel there, clean it out. Simple Green works quite well, but so does brake cleaner or engine cleaners. Make sure the drains flow freely. Open it up and get an eyeball on the filler tubes going into the tank. They need to be dry with no evidence of fuel ever having leaked.
If the coach has long range tanks make sure the connections between tanks are dry and free of fuel stains. Look on top of the tank to make sure the connections, gasket, and everything is clean and dry. Use whatever it takes to get a visual on these things such as mirrors or getting under the coach.
If everything associated with the coach fuel tank(s) checks out start following the fuel lines to the generator, engine, Webasto, Aquahot, etc. You may end up cleaning every hose and connection just to make it easier to see wet spots or evidence of leakage.
But keep in mind one thing. If you can smell diesel fuel inside the coach you can be assured the chassis is not properly sealed. Our coaches need the house portion completely sealed from the outside. We have a lot of penetrations for wiring, pipes, sewer pipes, etc. but regardless of where or why something passes from the outside to the inside it needs to be sealed air tight. So after the leak or spilled fuel is located, the next step has to be to seal entry points for odors.
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Charlie,
I had the exact Diesel fuel smell in my coach shortly after I bought it.
Does your coach have OTR air?
If so, what mine was doing was this……..The OTR air bay is next to the fuel fill on the drivers side, which actually shares the same bay door. The bay door has a rubber seal around it, and it seals around the fuel fill door as well. Mine was missing a piece of the rubber seal around the section by the fuel fill. I ordered a new seal from Prevost,and I replaced only the section that was missing, and my fuel smell went away.
The OTR air was sucking fumes from the fuel fill area, tank area etc. and sending the smell through the squirrel cage fans on the OTR air into the ducts inside.
Hope this helps!
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Interesting: I just had some service work done on my generator, had it checked for leaks and steam-cleaned. Found a leak on the fuel filter that was causing some mess on the floor of the generator bay. Hopefully that is some of it..
Great ideas and appreciate everybodies assistance.
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If you have diesel fuel in the generator box and you can smell it inside the coach I would suggest looking for some opening that is allowing the fumes into the coach.
If a fuel smell can get in, then carbon monoxide from an exhaust leak can get in.
I would also make sure the generator box has a working fan to exhaust those fumes when the generator is in the start mode or running. I don’t think the fire or explosion hazard on a diesel generator exists like it does on a gas generator but I wouldn’t want to test that theory.
Finally, when the generator is running for extended periods the smell of a leak in the box should go away because the generator is ingesting air from within the box and those fumes should be drawn into the generator intake.
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