Best oil level for a Diesel engine
 

What is the best oil level for a 27 years old 617.912 Diesel engine?

A friend of mine told me that it's best to keep it between middle level and 3/4, too much being bad on the oil pump/system. From my experience the engine sounds better when the oil level's between middle and full level but I want to know what would be the best/recommended level for this type of engine. Note that it doesn't use up any oil so I need to get it right once/oil change.

General concensus is halfway between full and add mark...at full mark consumption increaces...and on the other side its never good to have it below the full mark. But realisticly anywhere between that is fine. Changing it regular and on time is far more important.

Strange problem I have, related to this.

Before I found this place, I used to fill up with 10W30 (I know, I know.. horrible to do that).. which would register perfectly on my dipstick. Now, when I use the same amount of Rotella-T, it registered at about the too-full line.

Is this normal.. I assume it's not.. in which case.. what the heck would cause this? :P

Engine has no blow-by, and a small oil leak from the filter housing.

boy...thats a good one. Whaddya think BHD?

Cheers,

Bill

odd.....Full with filter change on a 617 is 7 quarts....(remember oil lines and cooler are holding oil too) can't explain it...maybe viscosity of the oil at room temp? THe rotella-T flows quicker and registers sooner? Just a theory. I have no answer for that one.

The car is a 1984 300D Euro (with an aftermarket turbo). 7 quarts? Huh.. I usually put 7 1/2 in.

On a totally unrelated note.. what is the size of the fuel tank on this thing? 18 gal?

How were you buying your 10w-30 and for that matter your Rotella? You usually don't see Rotella in quart bottles, and you usually don't see 10w-30 in gallon bottles. If you use 8 quart bottles vs 2 gallon bottles, you will actually be delivering more oil into the engine from the 2 bottles vs the 8 bottles. If you let them drain long enough the difference is pretty small, but if you have 8 bottles to dump you are likely to get in a hurry and not let them drain quite long enough. Just a hypothesis, I'm probably full of crap...

Any chance one was quart bottles and the other liter bottles?

the Wagon had the 18 gallon tank...the sedan had a 20 or 21 gallon...don't remember the quoted spec.

According to MB between the low mark and high mark. Half way seems to be the best some engines will burn oil until it is down to the half way mark.

oil level
 

A higher viscosity oil may stay in all the crank/rod journals and other machine fits so may not drain back to the pan after shutdown. Just a guess.

For you 603 owners, I remember reading a post here, might even have been from Marshall Booth, or referenced such from, anyway the message for the 603 was to not fill to the full mark on the stick, but half-way between.....

Recycled
 

To answer many customers question...
Important NOTE:
For the most accurate level reading; Check the engine oil COLD or 45 minutes after the engine is turned off.

IMO; running half a quart below the full mark is the best balance.

FWIW, I find that the 617 uses the least oil when it's level is maintained just above the low mark.

In 5K, I can get away with about 1.5 quarts...........otherwise, if held above the middle of the range, it will use close to 3 quarts.

We are finding this out as well on our wagons 617.952. It almost seems as if the car quickly burns off the oil if it is filled to the top line when cold but as the level gets closer to the bottom line on the dipstick then it stays that way longer? Did they make a mistake when they marked the dipstick? It seems to me in one of the two cars the engine seems to run better with less than full oil....faster or more freewheeling like more oil equals more resistance in the crankcase? My 300d non turbo is this way as well. why?