Urgent Yanmar oil dipstick measurement question

[smokey73]

I have a Yanmar 4JH2(E)

When I take the dipstick out in the morning to check the oil level, first thing, before it has been started or anything, the dipstick shows oil only on the very tip of the dipstick. If I then take clean it off and put it back in (never having started the engine or done anything that would change the level), it is at the the upper line (full) on the dipstick.

What gives? Is the first reading with it sitting all night the right reading and I need to add a lot of oil or is the second reading correct? All my life when checking oil I check it first thing and then clean it off and check it again and the readings aren't all that different.

I don't want to overfill it but I don't want to run on the hairy edge of out of oil? We are on a transit down the ICW and I have internet tonight so maybe someone can let me know what is correct.

Thanks

 

[weinie]

My universal engine does it too. Probably just air trapped in the dipstick tube after the engine is shut down and the oil returns to the sump trapping the air.

ETA: Gave me a good scare the first couple of times before I realized what was happening.

 

[transmitterdan]

My 4JH3 does the same thing. I agree it is air in the tube. The dipstick has a rubber seal at the top of the tube that keeps the air from leaking out.

 

[Benny17441]

To take a dipstick reading you should pull it out wipe it and then take a reading. I would say your second reading properly conducted is the correct one. Why when you first pull the dipstick it shows a low level I would not want to speculate. But in order to set your mind at peace go ahead and turn the engine on and let it warm up and then shut it off allowing a few minutes for the oil to return to the cranckcase. Take the dipstick out, wipe it and then take a reading; whichever level matches closely the ones taken earlier will be the correct one. Like I said it should be the 2nd one. Maybe it has something to do with oil sticking best to a dried surface.

 

[Rick D]

Same Here On 4JHE

nm

 

[kbuckley]

I agree that the second reading is the correct one.

 

[smokey73]

Thanks all!

You have put my mind at ease. I don't like seeing the oil level on the dipstick that low and most if not all of the other engines (car, tractor, etc) I have had did not demonstrate this trait. Glad to know I'm doing it right then. It doesn't seem to burn any oil and the oil is remarkably clean for a diesel.

Thanks again.

Smokey

 

[Herrick18911]

I had known that the proper way to check oil was to pull dip stick, wipe off, replace fully, and then pull again and check level. I never knew why that first reading was always low. So it is due to air blockage? Curious.

Tod