Yanmar 3YM20 - Engine Oil API Service Category Question (+ Bonus Question)

[Jamme]

Hi all,

First DYI oil change; quick question on engine oil service category.

According to Yanmar manual, 3YM20 engines require an oil that meets or exceeds API service categories CD, CF, CF-4, CI and CI-4. The manual also states to never use (among others) CH-4 service category oils.

Some people recommended I use Rotella T-4, which I understand is the successor to “Rotella Triple Protection”. However, when reading the specifications, Rotella T-4 includes also API service category CH-4, not allowed by Yanmar. See screenshots below from engine manual and Rotella specs.

Question(s):

1. Can I safely use Rotella T-4 on a 3YM20?

2. Bonus question [emoji12]: would I be able to use the same oil (Rotella T-4) also as gear oil in a Kanzaki KM2P-1? Specs for KM2P-1 require a mono-grade SAE 20/30 oil.

Thanks and fair winds.

[tkeithlu]

Jamme, my suspicion is that they meant don't use CH-4 ONLY oil, such as Mobil Delvac CH-4. That's a special service oil made for Tata engines.

No, I'd use a single weight in a gearbox. The only surprise there is that they specified such a low viscosity. Most gear oil is near 90 weight. Multiweight oils are made for large temperature changes - 10W-40 is as fluid as 10 weight when cold and as viscous as 40 weight when hot. That's not really the conditions of a gearbox.

[Jamme]

Originally Posted by tkeithlu

Jamme, my suspicion is that they meant don't use CH-4 ONLY oil, such as Mobil Delvac CH-4. That's a special service oil made for Tata engines.

No, I'd use a single weight in a gearbox. The only surprise there is that they specified such a low viscosity. Most gear oil is near 90 weight. Multiweight oils are made for large temperature changes - 10W-40 is as fluid as 10 weight when cold and as viscous as 40 weight when hot. That's not really the conditions of a gearbox.

Thank you very much for the input. On the marine gear viscosity, apparently 90 is what they require on sail drive models (mine is not), see below.
Thanks again.

[Compass790]

I cannot understand why they ban CH-4 when this is from the API website, just saying, if in doubt follow the manual but I wonder if it's a mistake.

CH-4 Current Introduced in 1998. For high-speed, four-stroke engines designed to meet 1998 exhaust emission standards. CH-4 oils are specifically compounded for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can be used in place of CD, CE, CF-4, and CG-4 oils.

[Jamme]

Originally Posted by Compass790

I cannot understand why they ban CH-4 when this is from the API website, just saying, if in doubt follow the manual but I wonder if it's a mistake.

CH-4 Current Introduced in 1998. For high-speed, four-stroke engines designed to meet 1998 exhaust emission standards. CH-4 oils are specifically compounded for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can be used in place of CD, CE, CF-4, and CG-4 oils.

I agree! The maintenance manual seems more confusing each time I read it.
Thanks anyways.

[Niall leslie]

Dear Jamme,

I'd actually, as an ex. Yanmar dealer, recommend Rotella T-6 0W-40 or 5W-40 from the Shell range these days. Both are synthetic and will give superb service. The little extra cost is well worth it and since we use low sulphur diesel in North America they are appropriate. I'd recommend changing at the recommended intervals or each year in the Fall, whichever comes first. Use the specified oil in the gearbox.
Fair winds...

[Jamme]

Originally Posted by Niall leslie

Dear Jamme,

I'd actually, as an ex. Yanmar dealer, recommend Rotella T-6 0W-40 or 5W-40 from the Shell range these days. Both are synthetic and will give superb service. The little extra cost is well worth it and since we use low sulphur diesel in North America they are appropriate. I'd recommend changing at the recommended intervals or each year in the Fall, whichever comes first. Use the specified oil in the gearbox.
Fair winds...

Thanks Niall, much appreciated.

[Cadence]

I thought it was about engine oil does not gear box. The Rotella T's Ch 4 is probably just a
spec. that it is compatible with something calling for CH 4 in the viscosity range.
Use it in your engine.

[Jamme]

Originally Posted by Cadence

I thought it was about engine oil does not gear box. The Rotella T's Ch 4 is probably just a
spec. that it is compatible with something calling for CH 4 in the viscosity range.
Use it in your engine.

Thanks Cadence.