MapisM
Well-Known Member
Having recently debated this topic off-forum with a couple of esteemed forumites, and before that also with some MAN engineers, I thought to post a thread in order to:
a) share my findings so far, in case anyone else might be interested;
b) hear other, possibly different, views.
As a premise, I always used Mobil Delvac MX 15W40 as engine oil for the Cat 3116 engines of my previous boat, for no less than 17 years, with zero problems.
Btw, that oil always remained remarkably clear also after 100 hours or so, though I suppose that this was more down to the type of engines and their use at very low rpm/load in that installation.
Last year, I asked a MAN engineer who serviced the new to me boat in the past what type of oil he used, and his answer was Shell Rimula R4 15W/40.
At that time, after checking if such oil meets the MAN specs (which it does), I went for it, simply on the basis that it already worked for some 14 hundreds hours, and if it ain't broke, don't fix it.
But since then, I had the opportunity to talk with several other MAN engineers (another 3 of them, so 4 in total), and all of them confirmed that Shell stuff is their preferred choice.
This made me wonder if anyone else ever had the same feedbacks from other MAN service centers.
TBH, I tend to think that once an oil meets the manufacturer's specs, the type/brand is mostly a matter of picking whatever is more conveniently available and/or less expensive.
Also because in pleasure boats, engine oils are normally changed much more frequently than they are supposed to last, in terms of hours of operation.
But of course, if there's a widespread consensus about a specific type/brand, AOTBE I would stick to it, rather than switch to the Mobil stuff I was used to, as I was considering to do upon the next oil change.
Again, just a matter of it ain't broke etc.
Just for the records, the latest MAN approval code is M3277, which includes all their engines.
Pre-CR engines were instead designed for M3275 compliant oils, which are specifically NOT approved for CR engines.
As I understand, the opposite is ok, i.e. M3277 oils are approved also for use in pre-CR engines.
Apropos, another interesting topic is the usefulness (or not) of more modern oils on oldish mechanical engines, originally designed for fully mineral oils.
Sticking to the MAN example, there's plenty of full mineral oils which meet the M3275 specs (including the Mobil Delvac MX which I used in Cat engines), but afaik all M3277 compliant oils are semi-synthetic.
In other words, more modern engines seem to demand, unsurprisingly, more modern oils.
BUT, are these semi-synth oils worth using also on older engines, which kept running for years on mineral oils?
By "worth using", I mean strictly in terms of performance/protection, regardless of cost.
In fact, semi-synth oils are indeed a tad more expensive, but the difference is meaningless, when compared to other engine maintenance costs - let alone to the whole boat TCO!
Fwiw, on this specific point, one of the forumites with which I discussed this matter via PM already gave me his clear answer, which was yes, semi-synth oils do have several advantages valid also for engines originally designed to work with mineral oils. Otoh, he strongly discouraged full synth oils.
But I'll leave up to him to post more details, if he wants.
Time being, I was mostly interested in other views on this topic, also in order to check if the consensus on Shell which I experienced so far (albeit in a relatively small area, i.e. the N Adriatic) is reflected also anywhere else.
a) share my findings so far, in case anyone else might be interested;
b) hear other, possibly different, views.
As a premise, I always used Mobil Delvac MX 15W40 as engine oil for the Cat 3116 engines of my previous boat, for no less than 17 years, with zero problems.
Btw, that oil always remained remarkably clear also after 100 hours or so, though I suppose that this was more down to the type of engines and their use at very low rpm/load in that installation.
Last year, I asked a MAN engineer who serviced the new to me boat in the past what type of oil he used, and his answer was Shell Rimula R4 15W/40.
At that time, after checking if such oil meets the MAN specs (which it does), I went for it, simply on the basis that it already worked for some 14 hundreds hours, and if it ain't broke, don't fix it.
But since then, I had the opportunity to talk with several other MAN engineers (another 3 of them, so 4 in total), and all of them confirmed that Shell stuff is their preferred choice.
This made me wonder if anyone else ever had the same feedbacks from other MAN service centers.
TBH, I tend to think that once an oil meets the manufacturer's specs, the type/brand is mostly a matter of picking whatever is more conveniently available and/or less expensive.
Also because in pleasure boats, engine oils are normally changed much more frequently than they are supposed to last, in terms of hours of operation.
But of course, if there's a widespread consensus about a specific type/brand, AOTBE I would stick to it, rather than switch to the Mobil stuff I was used to, as I was considering to do upon the next oil change.
Again, just a matter of it ain't broke etc.
Just for the records, the latest MAN approval code is M3277, which includes all their engines.
Pre-CR engines were instead designed for M3275 compliant oils, which are specifically NOT approved for CR engines.
As I understand, the opposite is ok, i.e. M3277 oils are approved also for use in pre-CR engines.
Apropos, another interesting topic is the usefulness (or not) of more modern oils on oldish mechanical engines, originally designed for fully mineral oils.
Sticking to the MAN example, there's plenty of full mineral oils which meet the M3275 specs (including the Mobil Delvac MX which I used in Cat engines), but afaik all M3277 compliant oils are semi-synthetic.
In other words, more modern engines seem to demand, unsurprisingly, more modern oils.
BUT, are these semi-synth oils worth using also on older engines, which kept running for years on mineral oils?
By "worth using", I mean strictly in terms of performance/protection, regardless of cost.
In fact, semi-synth oils are indeed a tad more expensive, but the difference is meaningless, when compared to other engine maintenance costs - let alone to the whole boat TCO!
Fwiw, on this specific point, one of the forumites with which I discussed this matter via PM already gave me his clear answer, which was yes, semi-synth oils do have several advantages valid also for engines originally designed to work with mineral oils. Otoh, he strongly discouraged full synth oils.
But I'll leave up to him to post more details, if he wants.
Time being, I was mostly interested in other views on this topic, also in order to check if the consensus on Shell which I experienced so far (albeit in a relatively small area, i.e. the N Adriatic) is reflected also anywhere else.
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