D1-30 Black Oil

Sheepdog012

Well-known member
Joined
Jul 22, 2020
Messages
53
Fluid Motion Model
C-24 C SE
Hull Identification Number
fmlt2134c515
Vessel Name
Island Girl
HI Folks,

At the end of the season here and looking at the oil in my D1-30F with 167 hours on it. The oil was changed last fall at 75 hours so has about 90 hours on this oil and it was looking black mid season and is completely black now. Any thoughts on if this is normal for these little 3 cylinders? I will change the oil now but the manual says to replace every 200 hours or 12 months, but I can't see putting any more hours on this oil as a good thing. Any thoughts are appreciated!

-Sheepdog
 
Sheepdog,

I was told that is normal. I have change my oil about every 75 hours over the last 5 years and the only time it is not black is right after an oil change. I think you are good, however maybe a real mechanic can give you more information.

Dick
 
Below is just a copy and paste from an online article. Just type in, why does diesel engine out turn black so fast?, and you will find lots of info. I run approx 400 hrs per year on my D1-30 and change oil at or near the recommenced hours. As you have stated, shortly after an oil change it will quickly start to blacken. I use Royal Purple synthetic so it's pretty dark in color to start with but it doesn't take long before it's black. I'm not a mechanic either but I don't believe you have anything to be concerned with unless you have noticed performance issue with your engine.


While the diesel fuel is compressed during the engine's internal combustion process, more piston ring blow-by occurs. Remnants of the combusted diesel fuel turns to soot and when it moves past the piston rings it ends up in the engine's crankcase sump oil pan area, where the engine oil is stored. The soot created by a diesel engine combustion process is inherent to diesel engine design and is considered normal.
 
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