Mercedes OM 636 oil loss

[yanay]

Today while sailing I started the engine during a squall and the engine quit after 15-20 minutes. Checked the oil by removing the cap. The whole oil container was empty. Filled in 4 liters oil. Still empty. No oil in the bilge or heat converter water or out of the exhaust. No smoke in the engine room . Did not hear any irregular noise. It just slowly dropped RPM over a few seconds and stopped. I started it again and the same occurred. Did not see any traces of oil on the stern exhaust outlet, however I did not check smoke color from the back before it quit. Last oil change was in January and hardly added 350ml since then over maybe 70 - 80 engine hours.
I made it to Saint Martin WI anchorage on sails and anchored just now.

What do you think happened? Where did almost 8 liters engine oil go? What can I check first thing tomorrow?
Many thanks for your opinion!

 

[bristoljim]

What is your engine ? - what quantity of oil is a normal oil change.
jim

 

[bristoljim]

What is your engine ? - what quantity of oil is a normal oil change.
jim

"Checked the oil by removing cap" - why not the dipstck ?? - do you have an oil pressure gauge ?
Jim

 

[vyv_cox]

Assuming your oil pressure alarm works (does it sound when you turn the key but before starting it?) it will sound when oil is lost sufficiently for there to be no oil pressure. Even if this did happen the engine would probably not slowly lose revs, it would continue with ever increasing noise until it seized or broke.

It sounds rather more like a different problem with the information we have at present.

 

[Billjratt]

is the bellhousing empty?

 

[lusitano]

"Checked the oil by removing the cap. The whole oil container was empty" ???

What does the Dipstick say ?

 

[yanay]

What is your engine ? - what quantity of oil is a normal oil change.
jim

What is your engine ? - what quantity of oil is a normal oil change.
jim

Mercedes OM 636. 4-4.3 liter oil

 

[yanay]

Assuming your oil pressure alarm works (does it sound when you turn the key but before starting it?) it will sound when oil is lost sufficiently for there to be no oil pressure. Even if this did happen the engine would probably not slowly lose revs, it would continue with ever increasing noise until it seized or broke.

It sounds rather more like a different problem with the information we have at present.

Yes, turns out it was a fuel block at the diesel tank outlet which is less than 2mm wide and it is just fw of the diesel faucet. I removed the extra oil. Cleared the fuel block - a piece of sticky gunk, cleared the filters and the lines I could remove. Primary was slightly dirty, secondary clean. I installed new ones less than 20 engine hours ago. Primed the system. Clean diesel flowing freely. After that, the engine took some effort to start, fluctuated it’s revs and then quit by itself after 20 seconds at 1300 rpm. I let it sit for two hours and started again . It still chocked and fluctuated but at second try it kept running. However still it does not sound 100% to me. It is now running for 40 minutes at1100 rpm. What should I look at next? The fuel pump is TDZ. Is it likely it suffered from getting no fuel due to the block?

 

[yanay]

"Checked the oil by removing the cap. The whole oil container was empty" ???

What does the Dipstick say ?

I used the dipstick but under the heavy roll after the squall the readings were so extreme I could not tell what the level is. However my knowledge with Diesel engines is so meager I thought I should see oil in the container below the cap.now I know all oil is in the sump and not in the container.

 

[Tranona]

The "container" is called the rocker cover and just covers the heaad and valve gear and a convenient place to locate the filler cap. You should not be able to see oil in there.

Did you bleed the engine after sorting the fuel blockage? sounds like air in the system.

Suggest you clean the fuel tank or at least pump some fuel out of it from near the bottom to clear the gunge out if any, then get a diesel engineer to check the engine over and show you how to do basic maintenance including bleeding the fuel system.

 

[Biggles Wader]

If you put an extra 4 litres of oil in the engine when it didnt apparently need it you now need to check that it is not now overfilled.