Properly Check Engine Oil Level

[a64pilot]

Originally Posted by rwidman

I would have thought everybody would know to wipe the dipstick first. I guess teenagers don't play with cars anymore like we did back in my day.

As a guy that can legally overhaul Aircraft motors, I won't take offense, but I've not noticed one that would read significantly different before, not like this Yanmar anyway. I had to think about it a little while to understand why the readings were so different. I've always truth be known checked an engine when cold as in before placing it in operation as I believe it to be the most accurate and that is when I usually check hoses, belts etc anyway. Only engines I've personal experience with that had provisions for checking when the engine was running was Military 30 and 60 KW gensets, they had separate marks on the stick. Most engines have enough blow by that you don't want to pull the stick out when they are running anyway.

[Rustic Charm]

Wow, so many replies for something so ..... Common.

Seeing your a newly as you put it and you have had plenty of answers, can I perhaps suggest a simple clarification.

Check it cold before starting (every day)
Oil is in most manuals to aim half way between the low and high marks (not full mark or high)

And if you do check it for some reason after it's been running, let it sit for a period and definately wipe it off so you can see what the actual reading is.

[gamayun]

Originally Posted by Rustic Charm

Wow, so many replies for something so ..... Common.

Funny. This is exactly what my son says to those who ask simple questions about computer technology

[donsan48]

I have a 104.8 also and am having trouble determining my oil level. The dipstick is on the starboard side. I just bought the boat and the PO said he had just overhauled the engine. At first I thought it had just leaked out from the plug in the oil pan, but then I was reading somewhere someone was having a problem with the oil not showing at all on the stick. They said to moce the stick to the other side of the block where there is a bolt plug. So far, I haven't tried that, but will later.

[Cadence]

Originally Posted by gamayun

Funny. This is exactly what my son says to those who ask simple questions about computer technology

My problem is, I'm still looking for the dip stick on the computer. I think it is me.

[Reefmagnet]

If it hasn't already been mentioned, marine motors set at an angle quite often need the oil to be filled to a level other than the stock marks on the dip stick. My manual lists offsets for different inclinations and there is a fair amount of variation if the dip stick is well to the front or rear of the engine.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[sailormed]

On my Yanmar 3JH4E I have identified 2 causes of false oil level readings:
1-The rubber sealing at the top of the dipstick pipe is so airtight that after stopping the engine, the oil level raises in the oil pan but can not get into the dipstick pipe. The reading on the dipstick directly pulled out of a cold engine is always way to low because of this. Only reinserting it will give you the correct reading.
2-The oil in the upper engine part seeps only very slowly into the oil pan. If you check oil on the engine after 24-48 hours the oil has had time to seep down and the measured level is correct. If you check the oil after 1 hour on a still warm engine your oil level is way to low. To remedy this I open the oil filler cap, resulting in air access, giving a quick descent of all the oil into the oil pan. How to complicate something simple

[boeing1]

I check mine before starting, and regularly

[Rantum Scoot]

We have recently re-powered with a Yanmar 4JH4-TE (75hp turbo) and at the time of the first service which was done under the warranty I was advised by the Yanmar agent (and a very experienced marine engineer) that Yanmars, this model anyway, are notoriously difficult to get a correct oil level by dipping the stick. This is because the oil being dipped is enclosed in the dip stick tube which extends down into the crank case and whenever the dip stick is pushed down the rubber seals at the tope of the stick pressurise the tube much like a syringe which depresses the fluid down into the crank case thereby providing a false reading on the stick. His advice was service regularly with the stipulated amount of oil and as long as there were no leaks observed or oil being burnt then I was probably OK - indicating that it was probably a waste of time dipping the oil anyway. Needless to say I still continue to dip the oil as has been explained above but I intend to buy a second dip stick which I'll modify to enable the tube to be vented when being dipped to release the pressure and allow the fluid to rise in the tube to the correct level.

I wonder if any other Yanmar owners are aware of this or have found other solutions?

[Cadence]

Originally Posted by Lady Willoughby

We have recently re-powered with a Yanmar 4JH4-TE (75hp turbo) and at the time of the first service which was done under the warranty I was advised by the Yanmar agent (and a very experienced marine engineer) that Yanmars, this model anyway, are notoriously difficult to get a correct oil level by dipping the stick. This is because the oil being dipped is enclosed in the dip stick tube which extends down into the crank case and whenever the dip stick is pushed down the rubber seals at the tope of the stick pressurise the tube much like a syringe which depresses the fluid down into the crank case thereby providing a false reading on the stick. His advice was service regularly with the stipulated amount of oil and as long as there were no leaks observed or oil being burnt then I was probably OK - indicating that it was probably a waste of time dipping the oil anyway. Needless to say I still continue to dip the oil as has been explained above but I intend to buy a second dip stick which I'll modify to enable the tube to be vented when being dipped to release the pressure and allow the fluid to rise in the tube to the correct level.

I wonder if any other Yanmar owners are aware of this or have found other solutions?

Gee! A sane post with a sane solution.

[rwidman]

Originally Posted by Rantum Scoot

We have recently re-powered with a Yanmar 4JH4-TE (75hp turbo) and at the time of the first service which was done under the warranty I was advised by the Yanmar agent (and a very experienced marine engineer) that Yanmars, this model anyway, are notoriously difficult to get a correct oil level by dipping the stick. This is because the oil being dipped is enclosed in the dip stick tube which extends down into the crank case and whenever the dip stick is pushed down the rubber seals at the tope of the stick pressurise the tube much like a syringe which depresses the fluid down into the crank case thereby providing a false reading on the stick. His advice was service regularly with the stipulated amount of oil and as long as there were no leaks observed or oil being burnt then I was probably OK - indicating that it was probably a waste of time dipping the oil anyway. Needless to say I still continue to dip the oil as has been explained above but I intend to buy a second dip stick which I'll modify to enable the tube to be vented when being dipped to release the pressure and allow the fluid to rise in the tube to the correct level.

I wonder if any other Yanmar owners are aware of this or have found other solutions?

I wonder if Yanmar is aware of this problem and is working on a solution?

[a64pilot]

Originally Posted by rwidman

I wonder if Yanmar is aware of this problem and is working on a solution?

I wouldn't think so, mine is 27 yrs old and has the same issue, so it's existed for at least 27 yrs

[psneeld]

As some others have alluded to...an important variable is when you measure.


It should be the same every time, with the consensus that the drain down interval is long enough for the vast majority of oil to return to the pan.

[Rustic Charm]

I don't have a Yanmar, and I don't doubt you guys that do, but I don't understand why this problem is occurring

Surely, even if the pushing if the dip stick down with its rubber seal, causes some vacuum that then pushes the oil down to low, wouldn't it equalise by just letting it sit for ten seconds?

And secondly, on the Yanmar does the 'dip stick' tube go all the way to the sump? What I mean by this question is, on my Volvo and every earth mover I recall working on (cat, Hough, JCB) the tube for the dip stick ceased where it was usually screwed into the block. But below this, there was no tube and the bottom of the dip stick simply drops into the pan.

Again, I'm not doubting you guys, just seeking to understand the problem.

[a64pilot]

Originally Posted by Rustic Charm

I don't have a Yanmar, and I don't doubt you guys that do, but I don't understand why this problem is occurring

Surely, even if the pushing if the dip stick down with its rubber seal, causes some vacuum that then pushes the oil down to low, wouldn't it equalise by just letting it sit for ten seconds?

And secondly, on the Yanmar does the 'dip stick' tube go all the way to the sump? What I mean by this question is, on my Volvo and every earth mover I recall working on (cat, Hough, JCB) the tube for the dip stick ceased where it was usually screwed into the block. But below this, there was no tube and the bottom of the dip stick simply drops into the pan.

Again, I'm not doubting you guys, just seeking to understand the problem.

On the Marine engines it's common to suck the oil from the dip stick tube to change it, this of course means it has to go to the bottom of the sump.
Many do like me and use a smaller tube to slide down inside of the dip stick tube, but some use the dip stick tube itself.

Being a life long mechanic I thought it odd that I would get different readings with different techniques when checking the oil, but it wasn't too hard to figure it out and it's not hard to live with, a minor annoyance at most