I've never noted increased or faster consumption in the upper half, though definitely plausible. I fill to max tick mark during oil change then refill to max when I get to about 1/4 off of minimum.

I would imagine the thinner oil drains quicker than the thicker oil. The next time you do an oil change, drain the oil over night, let it all drip out.
My other theory is the thicker oil sticks to ( coats ) the internal engine parts better. either way more of the old oil stays in the engine.

Also , I want to know more about that aftermarket turbo set up.

It probably has more to do with the oil return from the separator. More pressure against this, and it'll throw more oil down the throat with the vapors instead of just dumping it in the pan.

yes, maybe...you are on to something, both separators were fixed with silicone and that helped with oil leaking from the air cleaner housing but I still find splashes of oil inside the housing, contained within the filter center section now? I though good to not be leaking out but why the splash of oil still in there, maybe the hose leaks a bit? the top hose is just push on type. the lower nipple on the separator has new o rings that are always broken.

Replying to the original question, I generally keep the '85 and the '87 between "half" and "full" on the dipstick but the '96 needs to be at or near the "full" mark or the low oil level alarm is unhappy. At first i thought it was the float switch and got a new one but no joy. Keeping the oil at full is the only thing that makes this particular OM606 happy.

I do not think MBZ would engineer the oil level to be so critical. I do not know whether the oil level between min and max mark is LINEAR, so it is moot to use it as a measurement for oil consumption at different fill level. My practice is to keep it between max/min and the oil warning light is out. That is good for me.

My 603s and M104s all get 8quarts at change time, fills to just above full, stays there for a couple of thousand miles or more with no leaks and no pressure problems, have done it for a couple dozen years and hundreds of thousands of miles with Mobil 1 oils, ... seems like the level isn't that critical.

Yeah, I'm a bad person and my cars seem to like it just fine.

My M103 developed a serious leak when it was about a year old though, seems that leaving the oil cap off after a change can let a lot of oil out of the hole :-(
The hood pad was never the same.

Couldn't it be argued that a higher oil level is better for bottom end lubrication?

ie - sloshing around and flung against cylinder walls.

Foaming isn't good, so an over-full condition where the crank can hit it would be bad.

Being slightly over or a quart low shouldn't have any effect on lubrication nor cooling, it's within limits. If the oil is low enough to affect oil pressure then there's a problem.

Pre-oil cooler engines (non-turbo) can benefit from more oil due to the additional thermal mass and increased contact with the pan for cooling, ... slightly.

Thats why if you look at a lot of the big motors from the 20's and 30's they held a lot of oil 2, 3 even 6 gallons isn't unheard of. Oil wasn't that good and they tried to keep them cool.

My non turbo 79 300D has an oil cooler? I wonder when they did not have an oil cooler for 617, maybe they gave us oil cooler motors and left the dipstick marks for cars without oil coolers? I wonder how many litres of oil those coolers hold for the sedan>wagon.? less than a litre? about a litre would actually make sense.

I always picture one of the elder members as an old german yoda looking guy that comes out of the back of a shop to declare the secret answer to this question....with a samurai sword too. Maybe, even, he used to build the older cars himself over in the german plants....


or


it's a conspiracy....

When I had a 603 I found it did not like to be overfull at all. In that motor to make the hoodline as low as possible they designed it to have the oil pan and oil level just as close to the spinning crank as possible, I believe.

None of my 616 or 617 motors bat an eye at an oil level that is 1/4" above the full mark. They are all in 123 bodies.

I had a 126 617 but that has been a good while and I cannot remember if it was any different.

I always slightly over fill at change, maybe 1/8" guessing that it will use that soon enough.

Has any one ever calculated how far off the crank the oil is when full? I suspect its a reasonable distance.
When you brake hard the oil runs forward ,could it fill the front enough for it to hit the crank?

I think that maybe much of the discussion being put up is "jumping at shadows".

If the oil level is best run low, I believe MB would have said so in their manuals.

The oil mark doesn't change for an oil cooler, the extra oil stays in the cooler and lines, it just has an increased oil volume.

The 603.96x has plenty of space between the full mark and crank/rods. The full mark leaves clearance for cornering etc., and enough space for the crank to not hit it at startup with all of the oil in the pan, has baffles in the pan.

On the longer-stroke 603.97x the pan is the same depth, same dipstick, still has clearance. There is a windage tray in the .97x engines though, might be an indicator of a closer proximity to the oil.

Answer
 

On the OM617 (engine off) there is minimal clearance when full.
When running; it (depending upon many factors) puts 2-3 quarts from the crankcase into circulation, and this is part of why you can NOT get an accurate oil level reading immediately after engine shutdown...
The OM617 does not want (FORD model-T) splash lubrication, it is a fully pressurized oil system.

Serious Danger:
* Oil Foaming = oil aerosol = crankcase vent feeding unregulated fuel through the intake manifold = a Run away diesel.
* Oil overfill = oil splash = oil aerosol = crankcase vent feeding unregulated fuel through the intake manifold = a Run away diesel.
* Lift pump leaking diesel fuel into the engine (making oil) = oil level rising + oil thinning leading to Oil Foaming = oil aerosol = crankcase vent feeding unregulated fuel through the intake manifold = a Run away diesel.



Run away diesel, why does it happen?
http://www.peachparts.com/shopforum/diesel-discussion/101404-run-away-diesel-why-does-happen.html


:( Goodbye engine, hello rebuild or good used engine...

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