Dirty Oil

[Rimica]

I have a Westerbeke 64 and the oil gets dirty very quickly (30 min of use) after changing it. Is this ok? I am getting a lot of conflicting advice on this.

Good advice would be appreciated

[Sailmonkey]

you will never change 100% of the oil. The remaining "Black" oil will color the clean oil very fast. An engine such as this, run under light loads, will blacken oil very quickly.
Normal.......

[David M]

That just happens with diesel engines. For some it happens quicker than others. I would suggest an oil analysis the next time you do an oil change. An oil analysis is a much better indication of a problem than the color of your oil. It will also tell you how "worn out"...for lack of a better word, your oil really is.

[stevensc]

Oil in a diesel engine normally turns back after a few hours as you have found out.
You really should change oil and filters per the manufacturers recomendation in the owners manual, if you have it, or probably available online. Otherwise go with an oil analysis provider for confirmation as suggested above, about 16-20 bucks per sample around here.
Good luck
Steve

[sailvayu]

An oil analysis is more useful for spotting trends over a period of time not great for a one shot deal. And you are not likely to understand the report without the help of a mechanic.

The black is carbon from burnt fuel being wiped off the cylinder walls by the rings. I would not worry to much as any oil left in the pan (and there always is some) will quickly discolor the new oil. change your oil and filter regularly and enjoy your boat. Watch for excessive smoke from the engine and have a mechanic check it at least once a year.

Fair winds
Wayne Canning, AMS
projectboatzen.com

[Chief Engineer]

Westerbekes and Universals are notorious for this.

There is oil that lingers in the passages.

[Rimica]

Thank you all. I will get an analysis done to give me a baseline that I will monitor over the years. My brother has a Yanmar of about the same size and his oil seems to stay cleaner althought his engine has 200hrs to mine 400hrs.

In the mean time I am looking forward to next spring.
Merry Christmas

[Ram]

my Yanmar oil looks clean 20 + hours after a change, my Isusu looks clean 20 seconds after a change!

[sailorboy1]

I'm gald it isn't just me. Changed my oil just prior to hauling recently. Ran the engine to run the anti-freeze though and it. Checked the oil afterwards and it was dirty already. I figured I hadn't managed to suck all the old oil out and figured it was me. So a little reassuring to know this is kind of common.