When I check my oil using the MFD when the engine is warm (30 minutes after engine stop), I get the message "1.0 quart low".

When I check my oil using the MFD with the engine cold (i.e. in the morning), I get the message "oil level ok".

When I check my oil using the dipstick, it shows up right about half way between the Add and the "too full" marks (i.e. right in the middle of all those ridge lines.

When I check my oil using the dyno mode, it reads about 4.7 quarts (cold).

So - do I have a problem or should I just trust the dipstick? If I'm in the middle of those ridges is my oil level correct?

Paranoid,
--S

Where did you buy your dipstick? Is it the one where you have to hit the floor of the pan to read?

I forgot to put in my signature - I own a 2002 which comes with a FREE dipstick! Oh, and a few more horsepowers. And a few more bugs, I hear (haven't encountered any yet at 1200 mi but I am paranoid).

---S

Yeh can you beleive a dipstick is not included on most cars?
Amazing.
One guy in another thread stated that the dealer refused to sell him one!
A freaking DIPSTICK, was to be used only by qualified MBZ personell. LOL!! I get better answers here than from the
"qualified" people at my local dealers.

Also posted was that oil consumption of up to 1 quart per
1000 Kilometers (not miles) was normal and didn't require anything to be done to the car.

So point being, you will need to add oil.
I'm going thru a quart every 2K miles or so,
and a dipstick is needed.

Just put one quart in and see what the computer says then!

steffen, according the the dipstick you are one quart low. According to dyno mode, you are 1.3 quarts low. According to the MFD when the engine is warm, you are one quart low. The MFD should not be used when the engine is cold. I would say that you are one quart low.

Do it in two 1/2 qt steps and see how it responds. Don't just toss a full qt in, it probably is OK but why chance overfill?

Lynn, if you read the manual it states that the MFD is only to be used when the engine is cold. At least 2 hours after it has ran. That is the proper way to use it. At 30 minutes after running the oil could be still in the engine and not drained all the way down yet. And when it is running there is at leats a quart or two in the engine so of course 30 minutes after you shut her down there will still be a quart still up there. Of course this all depends on engine design but the manual states the MFD should be used when all the oil is settled. About 2 hours after stopping the engine.

I'm pretty sure the manual for the 2002 states to check oil when the engine is warm, but turned off for about five minutes. Your manual could reflect a difference between the 2002 M111 and 2003 M271 motors.

Cheers, BT

Hey dude, where'd you get this info? My 2002 C240 manual (p. 141) states "wait 5 minutes". 2 hours? It's not molasses you know :p .

Actually, I think the synthetic oil they put in these cars is closer to molasses (more clingy) than regular oil. As I noted in another thread, I had to recently siphon off .2 Qts from my engine. The clear plastic tubing I used got coated with oil which would barely fall out of the tube into a glass jar. I had to hang the tubing over the jar all night (room temp: 40 degrees) before all the oil drained from inside the tubing.

IMO, I don't see how you can get an accurate oil level reading unless the oil is C-O-L-D. Like, 4-hours or more C-O-L-D.

Not to disagree, but... Every car I've ever owned said to check the oil when hot, at normal operating temp. They say wait a few minutes for the oil to settle down. The reading will be higher than when it is cold due to fluid expansion. I thought the dipsticks are calibrated for operating temp measurements, so I wouldn't be surprised if the level is somewhat down if checked when cold. Interestingly enough, the MB manual says wait about 5 mins. if the oil is hot, 30 minutes if it has not yet reached operating temp. I guess we'd have to experiment to see what the readings are at various wait points....

Synthetic oil does not cling to metal surfaces as well as petroleum based oil. As a matter of fact, when synthetic oil was first intoduced, Mobil said that it should not be used in engines which were not used frequently.

I have been changing oil in cars for over thirty years now, including just shut down large displacement V8 racing engines. There is no ****ing way there is 2 quarts of oil up in the engine after 5 minutes let alone 30.

The 2002 C coupe manual says to check the oil five minutes after shutting of a fully warmed engine. It also says to wait thirty minutes after shutting off an engine that is not at operational temperature. Page 141.

On my 1995 E420 the dipstick reading will be exactly between the low and high marks after an oil change and refill to spec. I believe the 1998 E320 that I had also measured that way. The newer models might measure differently. The next time the oil and filter are changed, make sure you can verify that the amount of oil used to refill the car is exactly what the manual calls for. Then check the dipstick after the car has been setting over night. This will give you the baseline reading for your car. Assuming the dealer changes it as part of the FSS, be positive that they refill to the proper amount. I have had experiences where the dealer will over fill by 1/2 quart.

This morning, my dyno mode said I had 8 Qts in the sump when cold (overnight cold). I then drove 17 miles to work (1/2 hour) and parked on level ground. 5 minutes after shutdown, dyno said I had 7.9 Qts. A minute later, it read 8.0. Still 8.0 after 10 minutes.

Anything to avoid walking inside to report for work...

Who knows--maybe it's set up like my electronic thermostat in my house. I set it to 72 and it locks on the temp you set to avoid showing you how the room temp really drops about 3 degrees before the heat kicks back on... only if it drops more than that does the readout show the "real" temp.

Anyway, thanks for the experimentation report

I do not have my manual now as my wife has the car, but I will check again. I thought the same thing when I read it. I have always just waited 5 minutes to check with a dipstick. Mine takes about 2 minutes to check when I do want to know. It takes longer if the engine is warmed up. I will check though and see what it says.

You are correct, I did drain back tests for Chevrolet's 502 program in the 80's and hot oil (200ºF+) drains back 98% in a matter of seconds.

Mobil has addressed and corrected this problem, it also used to be trouble in flat tappet engines (non roller) due to that issue.

Oil level is much higher with 8 qts. hot vs cold due to expansion. I can't remember the #'s off the top of my head, but it is substantial.