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Yanmar 3MY30 oil question

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Dec 27, 2005
Hunter 36 Chicago
This question may have been answered somewhere in the archives but I haven't been able to find a definitive answer. My Yanmar manual calls for an API rating of CD or better. However, it also states that the oil should not have the CG-4 or CH-4 rating. I recently changed oil with Rotella T (this is a new engine). I just noticed looking at the specs on the Rotella bottle that it has the CG-4 and CH-4 ratings along with a slew of other ratings. Question: is the CG-4, CH-4 a problem? considering that the CD rating is now oblsolete and the other additives may negate whatever problems were with the CG-4, CH-4 ratings. Another problem is I can't seem to find Yanmar oil or any other oil that fits the Yanmar specification.:confused:

Rick D

Jun 14, 2008
Hunter Legend 40.5 Long Beach, Shoreline Marina, CA
Before You Do Anything Else...

...call your distributor. They are the best source of information on this formulation. They will probably be conservative, but that is what you want at this stage and the worst that can happen is that you have to change the oil again, not a heavy lifting task.
Dec 13, 2006
Beneteau 323 Milwaukee
answer in wauconda

Mack Boring is in Wauconda Illinois. They are Yanmar distributors and can help you. MIke
Oct 29, 2005
Hunter 326 Singapore
Re: answer in wauconda

I had similiar questions when I was checking out oil for my friend's 3YM30. Then I realise Yanmar's engine oil also has the "-4" spec in them. So what the heck "....just do it."
Nov 6, 2006
Hunter 34 Mandeville Louisiana
I don't know why Yanmar would sanction CH-4 rated oil.. Most diesel oils today exceed that rating. (CI-4, CI-4+) There were some detroit Diesel motors that couldn't use normal diesel oils but it was because they used a lot of silver in their bearings. Yanmar does not. Mack Boring, as was suggested, is a great place to talk to about this, but I would think Rotella T would be a great oil for that motor!. I use Rotella T Synthetic in my 3 GMF.. Best check it out with MACK.. Please post the results of your inquiry to MACK for the record.. THANKS

The Yanmar website has this to say:
Which lube oil should I use for my engine and gearbox?
Any well known brand name oil for diesel engines will do, use mineral 15W/40 CF oil. Please remark if you have a turbo engine; make sure the oil is for turbo diesel engines. On gearboxes, it depends on what model you have, Kanzaki, ZF Hurth, Twin Disc, Newage or something else.

This from an SAE paper ..

This paper reviews ASTM's work in developing the new API CH-4 diesel engine oil category for 1998. In focuses, in particular, on three new engine tests ~ Cummins M-11, Mack T-9, and Caterpillar 1P ~ which are juxtaposed on existing engine and bench tests in the API CG-4/CF-4 categories. These new tests ensure increased engine durability, while operating at high temperatures and high levels of soot in the crankcase. The high soot levels expected in 1998 emission-controlled engines are a result of retarded fuel injection timing used to lower NO\dx, combined with high top-ring piston locations used to minimize particulate.
API CH-4 is the most robust API diesel engine oil category ever developed. It improves the quality of diesel engine oils for both existing and new engines, using both low and normal fuel sulfur levels. In addition, it will allow a more flexible approach to oil drain intervals, in accordance with the recommendations of the individual engine manufacturers

From another API (American Petroleum Institute) Paper:

API CI-4 oils are pivotal components in maintaining diesel engine durability using cooled EGR. API CI-4 is a higher quality oil than the previous diesel oil categories, so it will provide engine protection for both existing and new EGR engines.
Sep 20, 2006
Hunter 33 Georgian Bay, Ontario, Canada
I researched this quite a bit last year for my 3YM30 ....... came down to Rotella T 15W-40 for the engine and SAE30 for the trans.
Dec 27, 2005
Hunter 36 Chicago
Thanks for replies, checked with Mack Boring

Their response was that any oil with CF rating or better was OK to use with the 3YM30. Acording to the service person I talked to, the reason for the blurb about not using CG-4 or CH-4 was because Yanmar hadn't tested these type oils in their industrial engines a few years ago when they first came out with the CG-4,CH-4 ratings. They just inserted this caution in all their industrial manuals until they could test the oils with the ratings. According to the service person, the cautionary statement is obsolete now but hasn't been removed from their manuals .

Feel a whole lot better now.:)
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