Unusual Oil Level Issue

[Manny]

I have a Yanmar 3JH4E in the boat with approximately 450 hours and it is running beautifully. I do have one issue that I have noticed the last few years and I haven't been able to figure out the cause. Almost religiously, when running the motor for a while and returning to the dock and shutting down, I check the oil level. I usually let the engine sit for a while before doing this.
The unusual thing is that there are times where I pull out the dipstick, and find it is totally dry. I wipe it down and reinsert it and check a few times but nothing. I then add literally about an ounce but never more than two ounces of oil, and check again. The oil is then reading on the top mark of the dipstick... I have to imagine the difference between the top and bottom marks is more like a half or full quart. There have also been a couple of times that I have pulled it out, found it was completely dry, stuck it back in and checked, and all of a sudden the level is correct.
I never get the oil pressure light or overheat light, the exhaust is always clean without smoke or a sheen.

Anyone experience this, and if so, found the cause? Could it be the angle of the motor causing the strange levels?

 

[Tally Ho]

What if you checked it BEFORE running it?

I always check the oil in all my engines (cars, boat, home generator) before running the engine.

I am not sure how long it takes for the oil to drain back into the oil pan on a Yanmar.

Greg

 

[SoSound]

Anyone experience this, and if so, found the cause? Could it be the angle of the motor causing the strange levels?

Yes, almost every time I check, since it was new. I have no idea why.
¯\_(ツ)_/¯

I have a 3YM30 and when I check the oil before departing, my routine is; pull the dipstick, confirm there is nothing on it, reinsert and wait about 30 seconds, check again to confirm that oil level is normal. The first time I checked and saw no oil on it we probably had only motored for about four hours after leaving the dealer's dock. Seeing no oil on the dipstick was definitely a WTF moment.

 

[Manny]

Okay glad to hear it is not only me...
First couple of times it happened, it definitely had me extremely concerned.

And to answer the question about checking it before running the engine, I do that as well, especially when I remember I didn't get a chance to do that after checking it at last run. I've had the same thing happen in those instances as well.

One thing I didn't mention, there are times when I have added just a tiny bit of oil, and then found the oil level above the marks. Not a lot, but still very frustrating.

 

[Tally Ho]

Very interesting….never have had that happen on my Yanmar 2GM20F.

Greg

 

[Davidasailor26]

I wipe it down and reinsert it and check a few times but nothing. I then add literally about an ounce but never more than two ounces of oil, and check again. The oil is then reading on the top mark of the dipstick...

That part is stranger than mine. Like SoSound the dipstick on my 3YM30 is often dry when I first take it out, but as soon as I put it back in and take it out again it always shows the right level. I still wouldn’t worry; it’s probably just the same effect.

 

[kappykaplan]

Like SoSound the dipstick on my 3YM30 is often dry when I first take it out, but as soon as I put it back in and take it out again it always shows the right level.

Same for my Universal . . .

 

[jibes138]

This is conjecture but since the dipstick is sealed if a little pressure builds up in the tube from the crankcase it will force out the oil. When you pull the stick the pressure is released, the oil fills the tube, and life is good. My Universal M25 did the same thing.

 

[jviss]

This is conjecture but since the dipstick is sealed if a little pressure builds up in the tube from the crankcase it will force out the oil. When you pull the stick the pressure is released, the oil fills the tube, and life is good. My Universal M25 did the same thing.

Indeed, mine did, too. I'd pull the stick and it was dry, then reinsert it and the level indicated good. I suspect it's because the level in the sump drops when the engine is running, and the seal on the dipstick prevents oil from making its way up the tube when the engine is stopped.

 

[dmax]

Me too, scared the crap out of me a couple of times

 

[Manny]

Thank you all for the responses! I feel better about it now! I won't worry about it so much anymore but will continue to check the level.