Yanmar oil use

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robbieg

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My 3GM30F uses hardly any oil but my friends boat use about a pint every 25 hours. Both engines start fine & run well & don't seem short on power. Neither engine smokes noticably. I've told him his engines fine & jucst keep topping it up but he's worried his engine is on the way out.Anyone any ideas why the difference? Does using a pint of oil or so every 25 hours seem within acceptabel limits? Thanks.
 
1 pint of oil every 25 hours seems excessive. If I were you I wouldn't worry, but your friend should probably start to become concerned: if he's burning it then piston rings or gaskets spring to mind (you don't mention the relative ages of the engines) but then I'd expect to see a little blue smoke. If its appearing in the bilges then the fix ought to be obvious. I only have a 1GM, and normally don't need to top up the oil during a season. The external oil pipes are notorious for cracking and/or rusting, does the 3GM have these? Failing that it would be a good idea for your friend to find out where his oil is going. Out through the exhaust? (Another gasket problem?) It must be going somewhere!
 
As a precaution, I'd do a compression test. If all the cylinders are about the same, it can wait. If only one is bad, it could be a broken ring, and I'd investigate further as the bore and piston could get damaged if a broken bit escapes

Otherwise, if it starts and runs fine, and doesn't smoke, I wouldn't start throwing £££ at it to fix it. If I couldn't figure it out then sort it out without big bills, I'd live with it.

If the engine becomes more reluctant to start as the weather gets colder, I'd start planning for a valve and ring job. The compression test would suggest this is needed if compression is low on all cylinders.

If it still starts OK in winter, FWIW, my advice would be the same as that given by the doctor in Three Men in a Boat, something along the lines of, "Eat a pound of steak a day, drink three pints of beer and stop worrying."
 
On a no longer mine Yanmar YSB12 I tried to keep the oil level to full and kept filling up like your friend. After a few hours oil level dropped to halfway the lower mark.
When I once did not fill up, I found the oil level stayed stable midway between upper and lower level. Apparently when "full" oil was splashed around and burned.

Maybe worth a try?
Keep smiling
Theo.
 
pint every 25 hours is fine especially if the engine is really working hard.
if concerned still try a different oil and see if it makes a difference, has he tried your brand
 
What is the date of manufacture of your friend's Yanmar and has the oil consumption always been high? Yanmar built a batch of engines back in late 1990 which included the 3GM30F on my last boat, with a manufacturing defect which one could get corrected under warranty. The fault was their cylinder boring machine polished the bores to an extent that the engine wouldn't "bed-in" with resulting oil loss via the piston rings. It wasn't obvious from the exhaust but resulted in much higher oil consumption than one would expect.
 
A common problem with pleasure use of small high speed diesels is being "too kind". As well as hard work causing oil consumption, under work tends to glaze bores and use oil. Does your friend maybe treat his engine too gently? Is it spinning a short prop? If yes to either, try to get him to run the engine a little harder and see if consumption improves.
 
Oldhand said:
What is the date of manufacture of your friend's Yanmar and has the oil consumption always been high? Yanmar built a batch of engines back in late 1990 which included the 3GM30F on my last boat, with a manufacturing defect which one could get corrected under warranty. The fault was their cylinder boring machine polished the bores to an extent that the engine wouldn't "bed-in" with resulting oil loss via the piston rings. It wasn't obvious from the exhaust but resulted in much higher oil consumption than one would expect.
Click to expand...

Hi, I have a 3GM30F in my Ericson 32 (1985 but was repowered with the Yanmar some time ago) and my motor is consuming too much oil. I cam across your post about the factory warranty for this issue. Do you have any more information about it? The Yanmar US representative could't find anything about this issue but was referring it to the factory in Japan. If you have any information I'd appreciate it!
 
One disadvantage of using the old oils specified in the manuals for the GM series is that they do not contain VI improvers, which means they use more oil. Later oils will consume less but have other disadvantages (see many other threads and my website). My 3GM, using API CD oil, has always burnt some but not as much as a pint in 25 hours. I guess I top it up once or twice in 100 hours. It has now done just over 2000 hours but has always consumed about the same amount.
 
A FYI..
That is interesting.. I noted oil consumption 'that bears watching over the course of a year' when I bought boat with this engine.

Once I had removed the hi-rise bronze exhaust elbow/injection some 12 months later (!) and removed enough carbon crud within to restrict diameter to 50%, tadaah no oil consumption.

But more usefully, full revs achievable under load when 'static' and tied to the dock and no transom exhaust stain at the end of the following seasons..Run em 'ot and 'ard eh?
 
My Yanmar is a 3JH2-IIRC-and used an excess of oil untill I cottoned on that the oil the previous owner had used and left on the boat was American Quicksilver 5/20 weight.

Changing to Morris 20/50 suitable for petrol and non turbo diesels means no topping up between changes.

It may be something as simple as that-I hope so.
 
rotrax said:
My Yanmar is a 3JH2-IIRC-and used an excess of oil untill I cottoned on that the oil the previous owner had used and left on the boat was American Quicksilver 5/20 weight.

Changing to Morris 20/50 suitable for petrol and non turbo diesels means no topping up between changes.

It may be something as simple as that-I hope so.
Click to expand...
15/40 would be better
 
sailorman said:
15/40 would be better
Click to expand...

Why?

I have used 20/50 for five seasons with perfect results so far.

The engine has over 3000 hours on the meter, starts if you look at it, reaches full RPM without any smoke and pushes our heavy long keeler along at hull speed in flat water.

I have spent 50 years as a small engine mechanic, some of it with leading edge high RPM stuff in the 70's and 80's.

I am also very familiar with antique, vintage and classic engines and fairly familiar with oil specifications and properties.

I chose Morris 20/50 for many reasons, not least the fact that in my last business I was a leading stockist and I know I can rely on its quality.

In laymans terms, a 20/50 mineral multigrade will be as viscous as a straight 20 grade at low temperatures, and as viscous as a straight 50 grade at high temperatures.

A 15/40 would be the same bearing in mind the smaller numbers.

My Yanmar starts easily and readily at minus temperatures, has good oil pressure and reaches full performance when at operating temperature.

So the oil grade, to me, is not a problem.

Dont forget with lighter oil in it would empty the sump in ten hours cruising.

My fix works for me. That is all that is important.

It is also possible that others with oil consumption problems could find an inexpensive fix for a tired engine.

That was my intention................................
 
Because I need oil for my Yanmar 4JH4AE, I had a look at the info available:

The manual spec's API CH-4 or higher and SAE 10W -30 or SAE 15W-40

Yamnar's own oil is specified as:

API CI-4/CH-4/CG-4/CF-4/SL
ACEA E7-04/E5-02/E3-96/A3-02/B3-98

and SAE 15W40

Morris Golden Film SAE 20W-50, doesn't spec and API on the webpage and I can't get the tech data sheet to load, I get a server not responding error.

Yamnars oil is about £40 ( perhaps a little less if you shop around) for 5L

Morris oil is about £25 for 5L

On eBay I can get 5L for £17 - spec' API SL/CH-4, ACEA B3, B4, E3, SAE 15W-40

Which one do I buy???

The cost of the oil isn't a big % of running the boat (6L for an oil change, say, 10L for the year to top-up and I'll probably have some over)

But I don't like being ripped off, does the £17 oil do the same job as the £40 oil?
 
Ian_Edwards said:
Because I need oil for my Yanmar 4JH4AE, I had a look at the info available:

The manual spec's API CH-4 or higher and SAE 10W -30 or SAE 15W-40

Yamnar's own oil is specified as:

API CI-4/CH-4/CG-4/CF-4/SL
ACEA E7-04/E5-02/E3-96/A3-02/B3-98

and SAE 15W40

Morris Golden Film SAE 20W-50, doesn't spec and API on the webpage and I can't get the tech data sheet to load, I get a server not responding error.

Yamnars oil is about £40 ( perhaps a little less if you shop around) for 5L

Morris oil is about £25 for 5L

On eBay I can get 5L for £17 - spec' API SL/CH-4, ACEA B3, B4, E3, SAE 15W-40

Which one do I buy???

The cost of the oil isn't a big % of running the boat (6L for an oil change, say, 10L for the year to top-up and I'll probably have some over)

But I don't like being ripped off, does the £17 oil do the same job as the £40 oil?
Click to expand...
go to your local supemkt / motor factor & buy the cheapest 15>40 with the CF4 spec @ approf £14 per 5lts
 
sailorman said:
the lower viscosity would assist starting in cold weather
Click to expand...

Starting our engine is never a problem, no matter how cold it has been in the five seasons we have had her.

As the viscososity between 20/50 and 15/40 is very small in practical applications there is no detriment in using 20/50.

I was in Czechoslovakia in December 1989 with a Hyundai 1300cc petrol car.

In overnight temperatures of around -18 degrees it would not start-the dipstick could hardly be pulled out and the oil was like jam.

The local Autoservis put oil which was like piss in it and it started no trouble.

Two weeks later, halfway across Belgium on the drive home the oil light was on at idle and the engine sounded loose.

I drove home gently and changed the oil and all was well.

I dont know about you, but I'm up for winter sailing-but not at minus 18 degrees!
 
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