oily bilge water....where's it coming from?

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Matata

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Our bilge water colour is like a giant cup of tea! however there is an oily layer on top that is distinctly shiny orange golden in colour. I took a sample and let it settle for a month in a tall glass jar. The "tea" colour hasn't changed or settled but it does have this orangey oily skum on the top. Ive dipped a wick onto the top layer and it burns so its def petrocarbon . I reason that if it was engine oil it would be blackish. The oil filter surround is bone dry, so are the two fuel filters. Ive phoned Beta and in all their years very few gearboxes give problems, especially only 2 years old. Any ideas GREATLY accepted. Any suggestions what to do next? Pint of the "black stuff" for good suggestions! Nik
 
I bet it's diesel. My bilge looks the same, although I swore there were no fuel leaks. Very careful examination revealed that there were.

Is it like a Yanmar? My leak came from the secondary filter on the block - apparently a known problem area as the thread on the collar is too short to pull the bowl up tight.
 
Matata said:
Our bilge water colour is like a giant cup of tea! Any ideas GREATLY accepted. Any suggestions what to do next? Pint of the "black stuff" for good suggestions! Nik
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Could it be ATF? Try testing round the output shaft of the gearbox with the edge of a piece of newspaper. It could be the shaft seal, Technodrive gearboxes have a bit of "previous" in this respect.
 
If you have a traditional stuffing box it could be grease coming out with the dripping water.

Conventional wisdom says that you should have a regular drip. I changed my stuffing and now have virtually no drips or water in the bilge, and it doesn't overheat before anyone asks.Before, it was a wet and greasy mess, because I had to regularly over grease to keep water at bay.
 
I had exactly the same problem last year. Turned out to be a small fuel leak. The problem was a short length of flexible fuel pipe where it connects to the engine. The pipe looked OK on examination but the problem was solved by replacing the pipe.
 
the smell should tell you which oil of the three - gearbox will smell of sulphur, and diesel of diesel. Take a bit of each, have a sniff, then have a sniff at what is floating on the water.

Clear oil will likely be either gearbox or diesel.

What are you doing with water in the bilges anyway? Wooden boat?
 
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Thanks for all the suggestions so far. I'll draw a sample of the gearbox oil as a comparison but you try getting to the back of the engine! I've taken up yoga! While i'm down there I'm putting in a new sterngland stuffing etc. We havent been too scientific about getting to the source of the oil but now that its out of the water... Yep your right 'bout the water in the bilge, there shouldnt be any at all. Maybe it all points to the sterngland? If it was a diesel leak would it be more likely to show up with the engine running......high pressure and all of that?Nik
 
Matata said:
Thanks for all the suggestions so far. I'll draw a sample of the gearbox oil as a comparison but you try getting to the back of the engine! I've taken up yoga! While i'm down there I'm putting in a new sterngland stuffing etc. We havent been too scientific about getting to the source of the oil but now that its out of the water... Yep your right 'bout the water in the bilge, there shouldnt be any at all. Maybe it all points to the sterngland? If it was a diesel leak would it be more likely to show up with the engine running......high pressure and all of that?Nik
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Not mentioned, so far, an exhaust leak - the symptoms point to this as the most probable diagnosis - certainly exhaust water containd hydrocarbons, mainly unburnt diesel.
 
Matata said:
Thanks for all the suggestions so far. I'll draw a sample of the gearbox oil as a comparison but you try getting to the back of the engine! I've taken up yoga! While i'm down there I'm putting in a new sterngland stuffing etc. We havent been too scientific about getting to the source of the oil but now that its out of the water... Yep your right 'bout the water in the bilge, there shouldnt be any at all. Maybe it all points to the sterngland? If it was a diesel leak would it be more likely to show up with the engine running......high pressure and all of that?Nik
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If the leak is in the pipe that takes excess fuel back to the tank it would not affect the running of the enginee!
 
Just thought I'd include a couple of fotos to give you a clue. Charles, I never thought of the exhaust water leaking! Do you think having a good look with the engine running might give me a better clue? Nik
 
You could try that - I found, in one instance, the leak was from the drain plug on the bottom of the Vetus water-muffler.

No evidence at all of leaks on the exhaust pipe.

I put it down to slovenly work by a boatyard - undid it to drain the system and forgot to do it up tightly.

The leaks, if any, usually aren't apparent on tick-over revs.
 
Matata said:
Our bilge water colour is like a giant cup of tea! however there is an oily layer on top that is distinctly shiny orange golden in colour. I took a sample and let it settle for a month in a tall glass jar. The "tea" colour hasn't changed or settled but it does have this orangey oily skum on the top. Ive dipped a wick onto the top layer and it burns so its def petrocarbon . I reason that if it was engine oil it would be blackish. The oil filter surround is bone dry, so are the two fuel filters. Ive phoned Beta and in all their years very few gearboxes give problems, especially only 2 years old. Any ideas GREATLY accepted. Any suggestions what to do next? Pint of the "black stuff" for good suggestions! Nik
Click to expand...
Hell of a water leak somewhere!! Its diesel
Stu
 
Unlikely to be exhaust - its too clean. Ditto engine lube oil. Therefore either gearbox or diesel and my bets on the diesel. Smell will tell. So will the gearbox dip stick.

Take some clean toilet paper and rub round each join on the diesel pipes. Bet you find one that marks the paper but if you dont, then start looking for leaks mid pipe. Pay particular attention to filters / housings.

Definitely nothing much to do with the stuffing box though the bilge water probably is. Try using a Volvo shaft seal instead.
 
Is there anything you guys dont know!!!! I'm a big believer that age is experience which would make the forum very old indeed! I will go down next week with a fresh pair of eyes. ta Nik
 
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