Diesel Smell in ER?

After reading the thread about gasoline smells in the ER (I would run, not walk away from gasoline fumes) I am curuious about diesel smells in engine rooms. I have been on tours of other boater's engine rooms and have more often than not smelled diesel. It seems to be accepted as normal. Of course it's not dangerous as gasoline is, but I feel if there is a smell of diesel, something is not right. On the diesel boats I have owned, if I smelled diesel in the ER, I would track it down. I use the edge or corner of a paper towel to test hose connections, injector fittings, and the edges around filter housings to see if any fuel wicks. Then I deal with it. It doesn't take much of a leak to smell up the ER. I'm not anal about most things but I hate that fuel smell. And if it begins to smell, I know right away there's a leak somewhere (I just got my oil analysis back indicating just a tad too much fuel in the oil so I'll find the source of that as well. I suspect a return line leak under valve cover.) . Same with water. I like to dry the ER sump with a sponge (FRP hull and dripless shaft seals) and when I see water in the sump I track down the leak. It's usually just a loose potable water fitting, but I like to know. In my experience when something doesn't seem right it usually isn't and I've regretted times I've ignored the clues.

My wife likes the smell of diesel. She even craved it when she was pregnant. I don't like it so I keep the leaks to a minimum and keep things clean.

On older wooden boats any diesel leak can get absorbed by the wood. On many FRP boats a diesel leak can migrate into the "hollows" such as stringers and keel voids. On vessels with a leaking fuel tank the wood supports can also become diesel traps for a very long time.

You are correct to be anal about diesel leaks, but on many vessels it is just the way it is and not necessarily a disaster lurking, as it can be with gasoline.

I've been lucky with diesel leaks. I've had a few and been able to deal with them. Poorly sealed tank connections and so on.
Of course some spilled while changing filters. Even with buckets and pans somehow I jostled them and slopped diesel.
Leaking stove when we first got the boat that soaked a bunch of cabinet area around it. The P.O. had been monkeying and really monkeyed the control valve.

The toughest to find was a pressure line to the cyl. head. It leaked only when running and not a lot but it stank the boat up. I finally had to spend some time down below with a flashlight while my wife ran the boat. Waiting untill dockside was useless because the diesel ran down the side of the engine block and flashed away after a couple seconds, before I could get down to check.

Now the boat only seldom smells and that's from other folks comments.

I agree though that leaks should be chased down but the lingering odour can be tough to deal with as it gets into everything including clothes, uphostery, wood. However if you stop the leak the odour will abate so it's worth doing, aside from the safety aspect.

My boat is 29 years old. It would take an entire roll of paper towels to sample for leaks. I accept the smell of Diesel in the ER like I do the smell of bilge water. Part of the joy of boating. I don't tolerate active leaks but there will always be traces and vapors in the ER.

Another note on diesel leaks. One of the major causes of ER fires, especially on turbo equipped diesels, is fuel injecotor lines rupturing and spraying fuel on a hot turbo. Because they are high pressure lines they can create a fine spray pattern or mist that is perfect for combustion. The lines may rupture from corrosion or fatigue. Fatigue may be the result of missing or loose piping brackets (the little clips that join lines together to keep them neatly in place). Loose or missing brackets may allow the lines to vibrate and shake. It's a good idea to check these at filter changes or when tightening hose clamps. You can see if any are missing by the lack of paint in those areas.

According to the BOAT/U.S. Marine Insurance Claim files, leaks in the fuel lines are the most frequent cause of diesel fires (Seaworthy, January 1990). Aged fuel lines can be as dangerous on diesel engines as they are on gasoline engines. Flexible fuel lines get hard and brittle as they age and must be replaced. Steel injection lines can corrode and develop leaks, and should also be examined and replaced as necessary.

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I do not think it is right to accept the smell of diesel in a boat as "normal". Primarily because it is a sign that something is wrong. Also, it stinks. It will permeate all soft goods and cause them to smell....even your clothes.

Baker, I was being a bit sarcastic.

I don't notice any leakage and I have rehabbed my engine room. The Odor persists. I run the blowers and vent the boat when I can. It's a normal smell to me.

As I stated I don't accept active leaks.

Diesel smell gives me a fix better than coffee in the morning. No leaks but 30 year old boat........

Baker said:

I do not think it is right to accept the smell of diesel in a boat as "normal".

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John: I think you are spending too much time over 30,000 feet, breathing all that recirculating air. I LOVE the smell of diesel and have purchased some diesel aromatic canisters just for that reason

rochepoint said:

Diesel smell gives me a fix better than coffee in the morning. No leaks but 30 year old boat........

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Diesel sniffing? I`ll stay with our onboard espresso machine.
We had some outback people "gasoline sniffing" for a fix. So unhealthy, fuel companies introduced a special gasoline for central Australia called "Opal", without whatever was giving "highs".

Maybe I am the odd one out but I dont have any diesel smell and I carry a 1000 gallons max and currently have about 700 gallons on board, if I smelt diesel at anytime or when checking the ER which I do daily, even if a slight whiff I would be down there pronto finding the source.

When boat shopping a smelly boat is one to walk away from right away at least in my humble opinion.

gwkiwi said:

Maybe I am the odd one out but I dont have any diesel smell and I carry a 1000 gallons max and currently have about 700 gallons on board, if I smelt diesel at anytime or when checking the ER which I do daily, even if a slight whiff I would be down there pronto finding the source.

When boat shopping a smelly boat is one to walk away from right away at least in my humble opinion.

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Fully agree on both counts!!!

I don't mind the smell of diesel exhaust. But the smell of degrading diesel mixed with salt water in a bilge is horrible. Reminds me of my college offshore sailing days or working in the bilges on the sub. Hangovers may have played a role in both memories though.

When I repowered, replumbed and painted my bilges in my boat all diesel smells disappeared.

I run a 110 volt inline blower all year round to create a small vacuum in the engine room and bilge. I have no smells issue on board the fan has been running for 8 years it use very little power.