Oil Levels

[KREW2]

How long does it take to settle back into the sump after running?
I ran the engine, a raw water cooled VP 2002 for about 25 minutes, some 15 minutes after stopping it, I checked the oil level, and it was very low. I topped it up with just over 1 ltr, re-dipped it several times to find it was now reading 2" above the full mark. Anyone any ideas how this could be.

 

[wotayottie]

You probably topped it up with too much oil. The top up oil being cold will take a lot longer to get down to the sump so if you dip it quickly and then top up a bit more, you will overdo it.

 

[VicS]

How long does it take to settle back into the sump after running?
I ran the engine, a raw water cooled VP 2002 for about 25 minutes, some 15 minutes after stopping it, I checked the oil level, and it was very low. I topped it up with just over 1 ltr, re-dipped it several times to find it was now reading 2" above the full mark. Anyone any ideas how this could be.

Obviously takes longer than you allowed to drain down.
A litre is more than I would top up a smallish engine with in one go

The manual says to check the oil level before starting the engine.

Whatever don't run it this much over filled

 

[noelex]

I have noticed our Yanmar engine has a unusual quirk when measuring the oil level. The oil level goes down a few minutes after shutting down the engine. I can only think the hot engine creates a vacuume that sucks oil up out of the sump. If you wait 10 mins as Yanmar recommends is back to normal.

 

[Medusa25]

I pull out the dipstick when filling as this gives the air somewhere to escape from
this makes it settle down a little quicker.

 

[KREW2]

I have noticed our Yanmar engine has a unusual quirk when measuring the oil level. The oil level goes down a few minutes after shutting down the engine. I can only think the hot engine creates a vacuume that sucks oil up out of the sump. If you wait 10 mins as Yanmar recommends is back to normal.

That makes a bit of sense, as it was a hard job to get the oil filler cap off, maybe taking it off released the pressure.

 

[VicS]

That makes a bit of sense, as it was a hard job to get the oil filler cap off, maybe taking it off released the pressure.

I think perhaps you need to look at the crankcase breathing if there is any evidence of pressure build up

Something niggling in the back of my mind about crankcase breathing on these.

 

[KREW2]

Obviously takes longer than you allowed to drain down.
A litre is more than I would top up a smallish engine with in one go

The manual says to check the oil level before starting the engine.

Whatever don't run it this much over filled

I will remove some before I start the engine.
The manual says the capacity of oil in the system should be 2.79 ltrs, as it was showing well below the mark I didn't think 1 ltr would take it up so high, so maybe it was being held up in a vacuum.

 

[KREW2]

I think perhaps you need to look at the crankcase breathing if there is any evidence of pressure build up

Something niggling in the back of my mind about crankcase breathing on these.

Interesting point, I will google it now
Ta

 

[VicS]

I will remove some before I start the engine.
The manual says the capacity of oil in the system should be 2.79 ltrs, as it was showing well below the mark I didn't think 1 ltr would take it up so high, so maybe it was being held up in a vacuum.

I am afraid I cannot quite work out how you would get a vacuum preventing the oil draining back to the sump.

Presurisng of the crank case maybe if the breather is blocked

 

[KREW2]

I am afraid I cannot quite work out how you would get a vacuum preventing the oil draining back to the sump.

Presurisng of the crank case maybe if the breather is blocked

That's what I meant.
Just on a technicality, would a blocked breather pipe not allow the oil to drop due to it causing a vacuum, or is it just pressure in the sump not allowing it to fall?

 

[VicS]

That's what I meant.
Just on a technicality, would a blocked breather pipe not allow the oil to drop due to it causing a vacuum, or is it just pressure in the sump not allowing it to fall?

The breather I think is an internal passage between the top cover and the inlet manifold.
There is a warning in the manual to fit the cover gasket correctly so as not to block it.

I think all this about crankcase breathing is a red herring. I don't think any pressure build will affect the oil flowing back to the sump.