Best oil for Yanmar 2qm20

Cheapest 15/40w mineral oil to CF spec available from Tescos (and other similar stores). Labeled as suitable for older diesel cars.
 
No.
A decent brand of oil that meets the spec that will have a good additive package for anti wear and anti-corrosion.
If you prefer non-synthetic, then you still want a quality brand such as Miller's .
As it's a full flow filter, you want a detergent oil, not a non-detergent type.

Ironically the cheap supermarket stuff will likely contain synthetics, among other things, as it's often recycled.

Cheapest supermarket stuff is for old bangers that drink oil and are headed for the scrapyard.
 
lw395 said:
No.
A decent brand of oil that meets the spec that will have a good additive package for anti wear and anti-corrosion.
If you prefer non-synthetic, then you still want a quality brand such as Miller's .
As it's a full flow filter, you want a detergent oil, not a non-detergent type.

Ironically the cheap supermarket stuff will likely contain synthetics, among other things, as it's often recycled.

Cheapest supermarket stuff is for old bangers that drink oil and are headed for the scrapyard.
Click to expand...

Rubbish. It meets the API CF spec which is actually higher than the minimum recommended by Yanmar.

Small diesels do not require fancy oils. They have low specific outputs and run at constant speeds well below maximum outputs and the oil is changed in a yacht engine at low hours typically 150, which in road vehicle terms is less than 5000 miles.

£12 for 5 litres in Lidl this morning.
 
Tranona said:
Rubbish. It meets the API CF spec which is actually higher than the minimum recommended by Yanmar..
Click to expand...
for the first hour of operation.
What CF does actually specify?
There is a lot more to oil than just viscosity.
Tranona said:
Small diesels do not require fancy oils. They have low specific outputs and run at constant speeds well below maximum outputs and the oil is changed in a yacht engine at low hours typically 150, which in road vehicle terms is less than 5000 miles.

£12 for 5 litres in Lidl this morning.
Click to expand...
Small diesels still shock load their oil films like any other diesel.
Save a few quid on oil, against possibly extending the life by several years.

Yanmar, like everybody else, specify what is widely available worldwide when the engine is launched.
If you look at their own brand oil, it's actually fairly highly spec'd now.

As you say, a lot of yacht engines do low hours, but there still seem to be a lot of smoky knackered ones being replaced.
Same as a lot of 60's cars were pretty tired after low mileages on 60s oil.
 
lw395 said:
Yanmar, like everybody else, specify what is widely available worldwide when the engine is launched.
If you look at their own brand oil, it's actually fairly highly spec'd now.
Click to expand...

As a matter of interest, what oil do you have in mind?
 
Synthetic and semisynthetic should not be used or recommended for engines when mineral has been specified by the manufacturers.

Yes, I know some misguided owners do (use synth & semi) and without problems but just because an "improved" oil becomes available it does not mean it is suitable for older engines. Likewise modern low sulphur diesel (having poorer lubricating properties) that is unsuitable for some older engines - but that's another thread !
 
theoldsalt said:
Synthetic and semisynthetic should not be used or recommended for engines when mineral has been specified by the manufacturers.

Yes, I know some misguided owners do (use synth & semi) and without problems but just because an "improved" oil becomes available it does not mean it is suitable for older engines. Likewise modern low sulphur diesel (having poorer lubricating properties) that is unsuitable for some older engines - but that's another thread !
Click to expand...

The pope has spoken!
 
theoldsalt said:
Synthetic and semisynthetic should not be used or recommended for engines when mineral has been specified by the manufacturers.
Click to expand...

That's only because the manufacturer specified the oil available at the time they designed and built the engine and can't be bothered to re-do all their longevity testing when new oils become available.

I've been using fully synthetic oil in road vehicle engines since Mobil 1 synthetic was first launched in the mid-70s even though mineral oil was specified for all those vehicles for the next 30 years. Those engines all benefitted from running on synthetic oil rather than mineral as was apparent when stripping them down. Had I followed the manufacturers oil recommendation I would probably have spent more time and money on engine maintenance.

Nothing is ever as simple as it first appears. :(

Richard
 
I love these oil debates :). My father used Shell Rimula (Err, R4 I think) and he was a marine engineer and a shipwright (I inherited his stocks and use them in Triola).

http://www.ebay.co.uk/itm/Shell-Rimula-RT4-X-Heavy-Duty-Diesel-Engine-Oil-15w-40-20L-/251201682736

Interesting write up here: http://coxengineering.sharepoint.com/Pages/Oilforyachtengines.aspx

If in doubt, talk to the experts at French Marine, they are always happy to help and have powerful magic.

My servicing write up of my 2GM20 is here (more for my own reference as much as anything!) - http://www.albinballad.co.uk/how-tos/yanmar-2gm20-engine-winterising-and-service/
 
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lw395 said:
for the first hour of operation.
What CF does actually specify?
There is a lot more to oil than just viscosity.

Small diesels still shock load their oil films like any other diesel.
Save a few quid on oil, against possibly extending the life by several years.

Yanmar, like everybody else, specify what is widely available worldwide when the engine is launched.
If you look at their own brand oil, it's actually fairly highly spec'd now.

As you say, a lot of yacht engines do low hours, but there still seem to be a lot of smoky knackered ones being replaced.
Same as a lot of 60's cars were pretty tired after low mileages on 60s oil.
Click to expand...

Afraid you are wrong. Nothing to do with viscosity. All that signifies is the thickness of the oil and is independent of the formulation.

CF is the API (American Petroleum Institute) grading which is universally used for grading oils. The higher the last letter up the alphabet in general the more additives to cope with higher duty. The recommended oil for Yanmar is CD, which at the time (30 years ago) that these engines were designed was the appropriate grade. CF is today's equivalent, although in some places you can still get CD.

The additives in higher spec oils are actually potentially harmful in old style diesels, mostly being there to cope with high outputs, tight tolerances and long service intervals - none of which are relevant to our types of engines.

Smoky knackered engines are little to do with the oil used, more to do with the way they are used and abused. Typical yacht running of short bursts followed by long periods of neglect is not good for engines and no amount of fancy oil is going to make any difference. The engine in my old Bavaria did well over 3500 hours, moat of it in 7 years of chartering using CF 15/40 and never burned any oil and runs as well now as it did when it was new.

Suggest you have a look on Vyv Cox's website for a fuller explanation, or do a search as this subject has come up here many times in the past.

www.coxengineering.sharepoint.com Explanation of oils under engines.
 
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John Teale said:
Hi all.

I am due to change the oil in my 1980 yanmar 2qm20 raw water cooled.

What are people using?

Cheers

John
Click to expand...

BP do a mineral based, single SAE 30 oil under their trade name of Vanellus, specifically for archaic diesels like the 1-2-3GMs..

It precisely meets the requirements of the Yanmar spec and costs €9 compared to the cheapest multigrade @ €29 for 4 litres.
I assume it's available in UK.
 
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