Proper Way to check engine oil level on Yanmar 2YM15

[NorthCoastJoe]

How can something so simple become complex?

On a stone-cold engine pull the dipstick and wipe it clean, oil will not be so runny.

Reinsert the clean dipstick and pull up careful not to rub the sides of the tube and keeping the dipstick vertical.

If any doubt do it several times.

[desodave]

I have a 15 year old 3JH4E and check the oil every day before I use the engine. Usually it's just pull the dipstick to break any vacuum, clean it and then measure the oil level. As the engine has aged, pulling the dipstick has not always broken the vacuum - the dipstick remains dry or almost so - and it has become more usual to have to release the oil fill cap to break the vacuum before getting an accurate measure.

[hpeer]

Yanmar 4JH4 with similar issues.

My sense is that small changes in pressure result in distortions. Maddening.

Roughly what I do is:
Remove dipstick and wipe it off
Wait like 30 seconds
Reinsert the dip stick
Wait 15 seconds
Pull dip stick and read (dip stick loop facing forward)
Reinsert and wait 15 seconds
Reinsert
Read
Repeat

I Want to get 3 pretty similar readings.

By waiting you allow the pressure changes from inserting the dip stick to go away. It does not take much pressure to push the small amount of oil in the tube.

But also, on my engine, the dip stick does a near 90° turn and enters the oil pan almost flat. A small pressure change moves the oil along the tube as much as or more than up and down. Thus even small changes appear to be large changes.

[capt jgw]

On my old Universal 5411 the stick was in a tube with a seal at the top. If I just pulled the stick out it would be dry or just a little bit on the end. Put it back in and check again the level would be on the mark. The oil pump sucks the oil out of the tube and the seal prevents it flowing back in. Break the seal and the tube will fill. Didn't seem to matter how long the engine sat between runnings up to several days. After figuring that out I would pull the stick out an inch or so, push it back in, then check. Level would be on the mark every time. My new Kubota engine has the stick just going through a hole in the block. It has a seal but no tube. It doesn't do this, I can just pull the stick out and read it. I miss the tube though, the dipstick is under the alternator and hard to reach.

On filling up to the top line, on most engines right on the top line is probably best. The dinner boat I sometimes run has old Detroit 8V71's (1964). Those are the kind of engines that if there's not oil squirting out someplace you's better pour more in. If we fill them to the top mark they'll blow it out all over the engine room till the level is about in the middle. Then it will stay there for several days. So we just try to keep it in the middle.

[sierramerkur]

Every diesel mechanic worth his salt will say FOLLOW THE MANUFACTURERS INSTRUCTIONS! An engine burning oil--is more reason to keep the engine full of oil--not half empty. In my opinion, the pictured dipstick showed a fuel diultion problem. Notice how the oil at the edges look very clear like mineral oil and the contaminant swirled in solution like black dirt? This is a worn out engine in my opinion. Dilution again is reason to keep the oil sump full and change the oil more fequently. A Chiropractor was going to rebuild his 1956 Chev Truck 250ci I-6 because it gave an occasional puff of blue smoke at start up. The compression was good. The engine ran great and the tiny amount of oil leaking past the valve guides (1 cup between oil changes) actually PRO-LONGED piston life like a 2 stroke motorcycle. I told him to leave the engine alone and keep the oil sump full. 10 years later he rebuilt the engine. 1956 Oil was a different beast and more oil is a good thing as long as it is not leaking on the ground/water. Engines with bad rings and oil dilution are losing compression and not far from the scrap heap.

[sierramerkur]

TideTime: Run away diesels always as you have indicated have unlimited access to fuel (or engine oil). This usually happens when a turbo is able to suck oil past bad seals and pump the oil into the intake. How does this happen on a nomally aspirated diesel? Broken governor & stuck Wide Open Throttle has nothing to do with internal engine oil leaks or Internal Oil leaks inside the 6-71 supercharger. Runaway engines most always occur in a shop with a mechanic horsing around and/or not paying attention to his work.

Run-away diesel engines have NOTHING to do with overfilling the crankcase. I repeat FOLLOW THE MANUFACTURER'S INSTRUCTIONS. When in doubt keep the oil sump full--but don't over fill. Engine oil (generally) doesnt have the expansion rate that ATF has. My post was directed to teach you how to "learn your engine:" And how to determine full on a hot or cold engine.

Stop the paranoia! Talk to a true diesel professional not a grease monkey who happens to work on diesels.

[Compass790]

Originally Posted by facciatosta

"Wow to me it looks like you have the bare minimum in there.
From your photos the oil on your dipstick does not go all over it, thats just the stuff that you have got smeared on it pulling the dipstick up the tube when checking it."

"The other side is picking up an erroneous reading from oil deposits left on the the dipstick tube which can show higher than reality."

Those were my initial thoughts. I panicked and overfilled engine with oil
No, it is not a smear. As previous commenters mentioned I checked not twice but many times.
Then engine had about 240 hours, does not produce visible smoke, does not leak the oil, It was filled per spec with 2 liters of oil. Where did oil go?
I lean heavily toward "the vacuum" theory. Especially because the pin hole on the top of the dipstick tube is definitely blocked by the the collar of the dipstick( design flaw or intentional?). I had to literally suck out some oil through the dipstick tube using the silicon tube and until I blocked that hole with my finger oil would come out.

I'm a bit stunned about how a supposed vaccuum could affect your oil level. I assume the 2ym15 has some kind of crankcase breather so no vaccuum can occur in sump & once you pull the dipstick any vaccuum in level tube should be broken.
Never experienced what you seem to have happening but without knowing your engine & its dipstick setup I'm just going to follow the thread with interest

I can see why its puzzling you.
Did you try putting 250ml in & seeing if the level rose on the dipstick to between the marks?
I mentioned that amount as it wont be a drastic overfill.
Is that its first oil change?
If you have done 250 hrs I wouldnt be surprised if it had burnt that much oil in those hrs or even 150 hrs.

[Lodesman]

Going out on a limb here and guessing that the tag on the dipstick is simply a warning not to check the oil immediately on shut-down, as the oil still has to drain back to the sump from wherever through the case. They've picked an arbitrary figure (10 min), but depending on how warm the engine is, how old the oil is, etc. etc. it might take a little less or a little more time to fully drain down. Solution - do what this guy said:

Originally Posted by NorthCoastJoe

How can something so simple become complex?

On a stone-cold engine pull the dipstick and wipe it clean, oil will not be so runny.

Reinsert the clean dipstick and pull up careful not to rub the sides of the tube and keeping the dipstick vertical.

If any doubt do it several times.

[Uncle Bob]

Why would one check oil level after use, surely a check would be best performed prior to use, or have I been doing it wrong for all these years?

[hpeer]

This is an old, old issue that has been addressed several times before.

I do not know if it is specific to Yanmars, but Yanmar owners have posted on this before.

One of the very first posts I made about my then new to me boat was this exact issue.

The first response I got was “Welcome to Yanmar.”

I think it is made worse by the near horizontal dip stick run, at least on my 4JH4.

[thinwater]

Why not just check it before you start the engine? Simpler.


Oh yeah. What Bob said.

[facciatosta]

Originally Posted by Compass790

Did you try putting 250ml in & seeing if the level rose on the dipstick to between the marks?
I mentioned that amount as it wont be a drastic overfill.
Is that its first oil change?

No, I have done opposite. On the cold engine I sucked some oil out and it went down to the full level mark.
It was my first oil change for this engine at 210 hours( when I got th boat). I can't imagine that 2 liters of oil would disappear after 50 hours of operation most of which were at 1,500 -2,000 rpm i.e. exiting the marina, dropping anchor, raising anchor etc.

[facciatosta]

Originally Posted by thinwater

Why not just check it before you start the engine? Simpler.


Oh yeah. What Bob said.

Right, that's how I have done before in all other engines.
Now trying to follow manufacturer's instructions.

[Lodesman]

Originally Posted by facciatosta

Right, that's how I have done before in all other engines.
Now trying to follow manufacturer's instructions.

Have you actually checked the manual?

[facciatosta]

Originally Posted by hpeer

This is an old, old issue that has been addressed several times before.

I do not know if it is specific to Yanmars, but Yanmar owners have posted on this before.

One of the very first posts I made about my then new to me boat was this exact issue.

The first response I got was “Welcome to Yanmar.”

I think it is made worse by the near horizontal dip stick run, at least on my 4JH4.

How is your Yanmar doing now?