Oil consumption

[Brian S]

I have a older Yanmar 2GM20F, don't know the year.
I'm burning about 1/4-1/2 cup of oil in fifteen to twenty hrs. of running at about 2400 rpm. Is this excessive? No visible smoke, must be burning up in combustion.
It's in a 30ft Catalina. I'm planning a trip across Sea of Cortez from San Carlos, then down to La Paz next season. Should I be worried. I've never had a diesel,and am learning. Except for that it runs great, no problems starting,good fuel economy. Any ideas? Thanks

[sailorchic34]

If it's starts easy and runs fine, It should be fine. Yanmars sometimes use a bit of oil. Odds are the oil control ring might be sticking a bit. Might trying running it at 3000+ for 15 minutes and that might burn the carbon off.

When it's 1/2 a quart in 12 hours and it hard starting then you have issues.

Check the crankcase breather. It might be clogged. Normally it's not. A long shot...

[MarkSF]

A cup is defined as being 250 ml. So you are using 100 ml or so every 20 hours? That's 500 ml every 100 hours, which is probably the service interval.

Sounds absolutely fine to me. Maybe your engine is getting a bit long in the tooth. But there's life in the old thing yet.

[CaptMarc]

"A diesel likes its oil, Like a sailor likes his Rum!"

Capt. Ron

[Lepke]

All engines burn some oil. The final honing of the sleeves/cylinders leave fine scratches at about 45°. Oil is carried up the sleeve to lube the top rings and upper bore. Over the life of an engine, these scratches are gradually worn away. Unless they are renewed, when they are gone, the rings and bores wear quickly and blow by increases.
If you engine starts, runs fine, doesn't leak, and not putting oil in the exhaust, don't worry

[sailorboy1]

Well I've had 2 different boats with Yanmar engines. One had 2000 hours and current one has 900 hours. With 7 years of my use of them neither used any oil in the normal for me use of 100-120 hours/year.

So while I don't think the OP necessarily has a problem, it definitely is not true that all engines burn oil.

[sony2000]

Sometimes using a different oil will help. Shell Rotella is an excellent oil.

[a64pilot]

As long as it starts easily, doesn't smoke excessively and makes good power, oil consumption is irrelevant.
I'll qualify that a little, if it never burned oil before and now is suddenly burning lots, well that means something is wrong, possibly a broken or stuck oil control ring.
Mine burns probably close to a quart in 100 hours and I consider that normal. There is some evidence that an engine that consumes some oil, the wear rate is less. That oil is lubricating the compression rings.


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[motion30]

1/2 cup of oil in 20 hours? I would say your motor is in excellent shape

[Whitebread117]

Our 74 Nissan diesel burns about a quart every hundred hours, which happens to be the oil change interval. It's a bit tired (only rebuild was in 83) but it's still reliable and I see no need to rebuild for minor oil usage. According to PO oil usage is unchanged for past 10 years.

Your usage is comparable - just keep an eye on your oil level and you'll likely get many more years out of it.