Oil out of Yanmar engine

[geek_guy]

I have a 3HM35F. I motored for 2 hours last weekend to find a small amount of oil in the bilge. Maybe 2-3 tablespoons.

I think I could see the wet trail from the back of the oil pan then forward to the dipstick. The dipstick is not tight and it had oil in between the ridges. So it appears there is some oil blowing out around it.

So do I need a new dipstick with fresher rubber, or is something else causing this.

Thanks

 

[woodster]

you may have not seated the dipstick all the way when you checked the oil ...word of caution don't overfill the engine with oil only the required amount (otherwise you could cause a runaway engine and that can get real harry if you don't know how to stop the engine by stopping the airflow) ...another place you can check for leakage is the breather tube going to the air intake on the side of the air cleaner/silencer.....

 

[Benny17441]

How many hours do you have on the engine? Like Woodster indicates check the oil level and that the breather tube is clear and make sure the dipstick is firmly set all the way. If it happens again after that you could probably blame a condition called "compression blow-by". As piston rings wear down some of the compression leaks down into the crankcase and create pressure. When this pressure gets high enough it can blow a dipstick out. One way of reducing blow-by is to go to a thicker oil or using a viscosity thickening additive. A thicker oil helps seal the rings and maintain compression in the combustion chamber where it belongs. To test, fire the engine up to idle, remove the dipstick and hover the palm of your hand over the opening; in a new engine you will barely feel air coming out but in a well worn engine you will feel strong pulsating bursts of pressure coming out. Also make sure that there are no fuel leaks into the crankcase that could have thinned out the oil and increased its level.

 

[woodster]

Also make sure that there are no fuel leaks into the crankcase that could have thinned out the oil and increased its level.

very good advice ...

this happend to me about 2 months ago ....oil level went to 2 and 3/4 qts on a 2 quart engine ...causing a runaway...shut engine down by closing the air intake on the silencer ...checked oil and found too much ....pumped out the oil and replaced with new oil .....checked the mechanical lift pump and found it to be leaking fuel into the crankcase..another symptom was oil pressure dropping to less than normal ...replaced fuel lift pump and all is good now .....engine did run quite fast for a few mins but got her shut down in time ....by jumping down below and choking it off from air ....got real lucky on that event ....it may have cleared out some other things by over revving but only a complete overhaul will tell ...but for now she is running to good to do that at this time

 

[Benny17441]

a complete overhaul will tell ...but for now she is running to good to do that at this time

I love it when an engine runs $$$ good.

 

[Bill Roosa]

if you engine set up is like most it slopes aft to allow it to engage the prop shaft. That makes the dipstick read wrong. Solution; upon the next oil change replace with the recommended amount of oil and oil filter. Start the engine and let the filter fill up. stop the engine and wait a few minutes to let the oil drain from the head. pull the dip stick and note the correct level of the oil. Write this down somewhere so you don't forget it. During operation eyeball the known correct "full" level and the actual level on the dip stick using the full and 1 qt down interval as a guide. the interval between full and 1 qt down is still correct just offset by the change caused by the engine not being level.
and make sure the dip stick is fully seated after you check it. Lots of folks have reported this issue and it has typically been failure to full seat the dip stick combined with over filling the engine to the actual "full" line when that actually results in an over full engine.

 

[geek_guy]

MMMM

I pulled and reput the dipstick 3 times. It still rattled in the hole. Pushed hard and it didn't seem to go in any further.
These old engines don't have an hour meter. So no clue on hours.
I'll have to try again. So no one thinks the dipstick become too small?

 

[woodster]

is the rubber grommet still on the stick take it out and take pic of it and post it on here so we can see what you have

 

[geek_guy]

Yes it still has the rubber piece. See pic. But it's odd that though it is inserted it is loose. I can wiggle it over an inch either way. When I pull it has no resistance. Which wasn't the case in past times.

 

[woodster]

can you move the grommet up and down the dip stick if you can it time to get a replacement stick ...they are not that expensive

 

[geek_guy]

NO the rubber doesn't move. But it is simply too small. Could there be a sleeve that should be inside the opening for the dipstick? Or the rubber shrunk? By the way a replacement dipstick is pretty pricy. 85 dollars. Though at this point I think that is what I need.

 

[woodster]

that is pricy ...i am not sure we have nailed down the problem .......if the rubber is not moving on the stick it should be ok ......do you know a marine/yanmar mechanic in the area that you can talk to...there has to be something else going on that we have not established .....if you do have a talk whit he and see if he has any ideas......

 

[geek_guy]

Ah Woodster. Sometimes I need a 2X4 up the side of the head. Good call. My mechanic has seen the dipstick flopping in the hole of the engine. Has replaced a few. He can't explain it either.

But I'm so lucky,,,,,,,the new dipstick is way cheaper than the one I found. A measely 75 dollars. ;-)

 

[woodster]

man thats great