Oil Questions

laika

laika

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From reading old posts I think I have the answers but given that this will be the first time I've done a minor service on a marine diesel engine I'd rather seem like an idiot than not ask..

I have a lovely newish Yanmar 3JH4E, the manual for which specifies "API CD or higher". As well as a couple of litres of the volvo CG4 / ACEA E3, I also have 5 litres of Turkish castrol turbomax tection (API CH4 / ACEA E3/E5/B2/B4/A2) left by the previous owner (and the previous engine). All 15W40. Obvious question is "can I mix the two?". I've seen the posts which say oils of the same spec can be mixed, but also that different spec oils have different additive packages which shouldn't be mixed. I wouldn't have any hesitation in mixing if this was a get me home thing but as I do have a choice and the engine is otherwise quite new, I am hesitating.

The other question relates to this being my first time changing oil with a suction thing rather than a container under the sump::
Would I be correct in assuming that a few drops of SAE20 gear oil falling into the engine sump from using the same sucky tube as just used to extract the gear oil is no big deal? And if not, is there an order (engine/gearbox) which is preferable to, errr, stick ones hose into (as it were...)? Cleaning the suction pump with a 1km walk between oil dump and water hose will be my next adventure...
 
Laika,

My policy has always been not to mix engine oils as oil is reasonable cheap. This may not be absolutely necessary but is the safest thing to do.
 
CD or higher seems an odd description. CD (although still available in UK if you search) is an obsolete grade now and Thornycroft accepted SF as a suitable alternative for our new engine. Main thing is not to mix old tech oils with semi or full synthetic. A few drops of gear oil in your pump out tube won't matter. As you have a newish engine, I would seek advice from Yanmar agent to avoid any potential warranty problems.
 
laika said:
From reading old posts I think I have the answers but given that this will be the first time I've done a minor service on a marine diesel engine I'd rather seem like an idiot than not ask..

I have a lovely newish Yanmar 3JH4E, the manual for which specifies "API CD or higher". As well as a couple of litres of the volvo CG4 / ACEA E3, I also have 5 litres of Turkish castrol turbomax tection (API CH4 / ACEA E3/E5/B2/B4/A2) left by the previous owner (and the previous engine). All 15W40. Obvious question is "can I mix the two?". I've seen the posts which say oils of the same spec can be mixed, but also that different spec oils have different additive packages which shouldn't be mixed. I wouldn't have any hesitation in mixing if this was a get me home thing but as I do have a choice and the engine is otherwise quite new, I am hesitating.

The other question relates to this being my first time changing oil with a suction thing rather than a container under the sump::
Would I be correct in assuming that a few drops of SAE20 gear oil falling into the engine sump from using the same sucky tube as just used to extract the gear oil is no big deal? And if not, is there an order (engine/gearbox) which is preferable to, errr, stick ones hose into (as it were...)? Cleaning the suction pump with a 1km walk between oil dump and water hose will be my next adventure...
Click to expand...

Hi- your Turkish Castrol is a higher spec. than required so if you have enough use it. Castrol are only blenders, not refiners and they package their products in the UK-or they used to-so UK Castrol of the same spec. would mix perfectly well. I have never had any detrimental effects from mixing low tech. oils in over 45 years of repairing and maintaining engines, but I know-or knew- enough about it to only mix oils that were compatible. If you are at all unsure, call Castrol's helpline-I feel sure they will have one. Good Luck.
 
If you refer to the oil spec table at the bottom of the page Engine>oil on my website you will see that API CH4 is formulated for higher sulphur levels than are currently available. The implication is that this oil has a high base number. Such oils are not good for lower temperatures, intermittent operation and constant throttle settings normally experienced by sailing yacht auxiliaries. I would not use that oil at all.

The CG4 may not be a bad choice but I don't have any more detail of its base number or levels of detergency. It does say that it is formulated for severe duty, high speed, etc., which is not normally a description of yacht engines. You would be better buying the closest approximation to API CD that you can get hold of, CF4 probably.
 
Thanks all. Yes the manual specifically stated "CD or higher". Vyv mentions the sulphur content CH4 is designed for. I had already referred to his oil page, and read there that both CH4 and CG4 are designed for fuels with sulphur content of "up to 0.5%". That table also says that CH4 may be used in place of CD, CE, CF-4 and CG-4 oils so especially given it's a pretty new engine I'm surprised by the "don't use CH-4" advice but happy to accept that CH4 is not ideal. For future reference, is there a problem with mixing CG4 and CF4 for example?

I also followed rotrax's advice. Marine advice is to be had from the "Industrial" rather than automotive advice line. Left a message for the guy who deals with that area on friday but not heard back yet.

May sound like I'm penny pinching but it's 30 quid's worth of oil, and this question will haunt me again when I'm somewhere where the same brand/spec that I already have a few litres of is unavailable
 
laika said:
May sound like I'm penny pinching but it's 30 quid's worth of oil, and this question will haunt me again when I'm somewhere where the same brand/spec that I already have a few litres of is unavailable
Click to expand...

I never worry about mixing brands, more concerned with the spec. At present (in Portugal) I use Galp Multidiesel which is available at many supermarkets. More expensive brand doesn't mean better quality.
 
In theory all engine oils are compatible with each other and are tested to be so. The reality is that there are so many different additive packages that it is an impossible task to be certain. You could try mixing the two in 10:90, 50:50 and 90:10 ratios which is what would be done in labs. Check for milkiness or other signs of reaction.
 
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