Disappearing Oil

[Charlie]

Here's the problem. I have a Yanmar 4JH4E with 630 hours on it. Oil changes have been done as scheduled. Originally I overfilled it with oil. I did not realize that if the engine was set at 8 degrees off of level you were supposed to underfill the engine by a half liter. There seems to be a problem with disappearing oil. I'll fill it with four liters of oil, the dipstick reads midway between full and add, then run the engine for half an hour and check the oil. When I check there is sometimes no oil and sometimes only enough to get the dipstick wet and sometimes it is at the add level. I try to make sure that the suction caused by Yanmar dipsticks does not cause a false reading. I add a liter of oil and it gets up to the add mark. I don't want to add anymore. I have a clean oil diaper under the engine and it is still clean after running the engine. I checked the exhaust and there is no oily residue. Where has the oil disappeared too? Any Ideas? I am a week late departing for the Baja Bash and now have to decide whether to do it or not.

[Boracay]

Your manual should give you the dipstick adjustments for engine angle. Mine (John Deere) is in the form of a graph. Get a level, a batten and a protractor and work out what your engine down angle is. It may be helpful to use some cardboard and scissors to make a wedge shaped template.

While the engine is running the oil splashes up and through the engine. It may take a few minutes to run back down to the sump, especially if it is cold. Look at your manual again for the correct way to check the oil level and for the amount of oil your engine needs.

The manual may be available online at the Yanmar site.

If you have fitted a new filter this will take additional oil.

I do think that it is wise to be concerned at this stage.

Don't forget to check your gearbox oil as well.

[never monday]

Charlie,
How soon after shutting down do you check the oil? consider having a beer first.

[skipmac]

Is this happening only after you change the oil and filter? If so, do you (if possible and your engine is not one with the oil filter mounted horizontally) fill the new filter with oil before installing it on the engine? If you can should do so for two reasons.

One, it is where about 1/2 Liter of oil goes when you first crank the engine.

Second, while the engine is pumping that 1/2 Liter into the empty filter you are taking longer to build oil pressure and adding wear to the engine and bearings while that happens.

Some other questions, what does the manual say is the total oil capacity of the engine? Is it the 4 Liters you add or are you adding based on dipstick level only? Are you sure you are getting all the old oil out when you change? A little too much in normal circumstances but in your case if you can't find an obvious answer I would check the dipstick before changing to make sure it's full and measure how much comes out to make sure you haven't left some in the block.

[Inthewind]

With some Yanmars, you will get a false reading when you first pull the dip stick. Pull the dip stick and ignore the first reading, then wipe it clean and check it again.

[Charlie]

Originally Posted by never monday

Charlie,
How soon after shutting down do you check the oil? consider having a beer first.

After shutting down the engine I wait for about five minutes. If I don't the oil shows all the way up and over the high mark on the dipstick.

Originally Posted by skipmac

Is this happening only after you change the oil and filter? If so, do you (if possible and your engine is not one with the oil filter mounted horizontally) fill the new filter with oil before installing it on the engine? If you can should do so for two reasons.

One, it is where about 1/2 Liter of oil goes when you first crank the engine.

Second, while the engine is pumping that 1/2 Liter into the empty filter you are taking longer to build oil pressure and adding wear to the engine and bearings while that happens.

Some other questions, what does the manual say is the total oil capacity of the engine? Is it the 4 Liters you add or are you adding based on dipstick level only? Are you sure you are getting all the old oil out when you change? A little too much in normal circumstances but in your case if you can't find an obvious answer I would check the dipstick before changing to make sure it's full and measure how much comes out to make sure you haven't left some in the block.

The engine does have the horizontal filter. I fill it about 3/4 full and then put it on. I expect to lose some height on the dipstick but not that much.

Originally Posted by Inthewind

With some Yanmars, you will get a false reading when you first pull the dip stick. Pull the dip stick and ignore the first reading, then wipe it clean and check it again.

Thanks that is a tricky one but I do as Chief Engineer suggests and pull the dipstick out far enough to break the suction and then lower it back in.