Yanmar Questions

[Horror Hotel]

As a mechanic I can tell you first hand that synthetic oils really appeal to the non- mechanical crowd as a feel good oil. My long time car nut friends know the value of just regular interval oil changes and quality filters. The folks who don't do their own service are more apt to want the better (perception ) more expensive oil as it gives them the feeling they are babying their car with something special. Surely the extra $5 a quart means it's doing what regular oil can't. I'm not into synthetic oil for any engine, borderline scam in my opinion. It very well might be slightly better but it's not like regular oil has failed us and we need something new. I do totally accept that it's not good for marine diesels, especially if we're talking about 20 plus years old. Unfortunately thats just the age of engine that the synth crowd feel needs the added help to keep running strong. The extra money and effort are causing more harm than good.

[d design]

This synthetic or no synthetic debate can get quite heated and it is all over the internet.

[Dockhead]

Originally Posted by Horror Hotel

As a mechanic I can tell you first hand that synthetic oils really appeal to the non- mechanical crowd as a feel good oil. My long time car nut friends know the value of just regular interval oil changes and quality filters. The folks who don't do their own service are more apt to want the better (perception ) more expensive oil as it gives them the feeling they are babying their car with something special. Surely the extra $5 a quart means it's doing what regular oil can't. I'm not into synthetic oil for any engine, borderline scam in my opinion. It very well might be slightly better but it's not like regular oil has failed us and we need something new. I do totally accept that it's not good for marine diesels, especially if we're talking about 20 plus years old. Unfortunately thats just the age of engine that the synth crowd feel needs the added help to keep running strong. The extra money and effort are causing more harm than good.

Synthetic oil has some clear and big advantages for highly stressed terrestrial engines -- the molecules actually lengthen with heat to keep viscosity and film strength up.

I wouldn't mind at all spending the money on synthetic if there were an advantage for my boat engine, and in fact, I have been spending the same amount of money for the Yanmar mineral oil -- paying the same premium but in this case in order to get a lower API grade of oil which better suits this application.

Another huge advantage of synthetic oil is that it doesn't break down nearly as fast as mineral oil in high heat applications, so you can extend oil change intervals. But we can't extend oil change intervals in our engines! The problem for us is not breakdown of the oil; the problem is accumulation of soot and acid.

[d design]

End of the day, use what makes you feel better.

[Dockhead]

Originally Posted by d design

End of the day, use what makes you feel better.

Naturally. Everyone of course has to decide for himself.

But one should also remember that how you feel will not influence whether it's good for your engine or not. That's why it's good to research the subject a bit and try to get at the objective truth of the matter.

[d design]

Seems to me that synthetic oil actualy is bad for old engines but nobody has experienced the effects.
Somebody post a video or pic of their damage. It speaks many more words.