pavichokche

I've been experiencing some strange behavior with my 2006 C230 in the oil level department. Basically, I'm getting occasional 'check oil level' warnings on my dash while driving, even though my oil level shows up fine on the dipstick.

To elaborate and tell the whole story, it all started a bit before my last oil change. I started getting the message almost every time shortly after getting on the highway. I checked the oil level, and it was right in the middle between the MIN and MAX part of the dipstick, meaning I was at about 7L.
The messages continued happening occasionally, rarely while off the highway. Yet every time I checked the oil level, it showed to be fine. So I did nothing until my oil change.

I drained the dirty oil into a collection pan, refilled the car with about 6-7L, idled it for a bit and checked the dipstick. It showed to be fine, so I left it. The very strange part - the dirty oil exactly filled up (to the brim) one of my 5L jugs, meaning there was just over 5L of oil in the car. So after the oil change I didn't get messages for a while, until I had to go on a long trip. I get on the highway, and for the first time in over a month I get the message again. I added some of the leftover oil (I had about 8L for my oil change and didn't use them all) and went on my trip, without issues. At the halfway point of the trip my dad was inspecting my car and checked the level, it wasn't at MAX so he tossed in all my leftover oil. After another maybe 1000km I got the message again, so I put in exactly 0.5L of oil (at this point I already wanted to keep things very exact). The oil level was always showing fine on the dipstick. And that's it, last oil I added was maybe 500km ago, I'm getting the warning occasionally, and the dipstick reads exactly on the MAX line.

I'm using castrol synthetic 5W-40 oil, and my car calls for 8L of it. I don't have any oil leaks which I can see or smell, and my engine is about as clean/dirty as it's always been, no visible changes.

This is all making me think that either:
a) my car is suddenly burning oil and my dipstick is somehow reading a too-high level
b) there is a faulty oil level sensor

Any thoughts, ideas, suggestions?

Plutoe

If your assessment is correct then you have a faulty oil level sensor.

pavichokche

So I went to the mechanic today, since I felt obligated to at least have it looked at.
The guy had no clue, said I was 1L low on oil, didn't see any leaks. He said if it was a pressure issue or something else the warning would have actually said so. I don't know if that's true, since in the manual it doesn't show such a warning. The only warning pertaining to oil is the one I got.

So now I don't know what to do. If I let the car sit long enough, it shows that my oil is above MAX. If I only wait 5 minutes to measure it, it's pretty close to MIN. If I wait longer, it keeps going up. I already added 1L over the weekend when I drove 1100km, I feel like if I add more it might be bad.

Does anyone know:
- if my car can show any warnings/messages that are NOT listed in the owner's manual?
- how low on oil the car has to be to warn me to check the oil?
- if the oil level measured when the car has been sitting for a few hours is accurate with respect to the measurement procedure?

Tuck G

I have a 2006 CLK 350 and the "check oil at next fill-up" warning happens every time within 2 or 3minutes of starting the car. My oil has been changed with 5w40 synthetic and oil level is at the full mark whenever I check it. I suspect the oil level sensor Has anyone solved the problem with a new sensor?

pavichokche

I'm going to change the sensor next time I change my oil in a month or so. I'll report back how that goes.

Tuck G

[QUOTE=pavichokche;7549512]I'm going to change the sensor next time I change my oil in a month or so. I'll report back how that goes.[/QUOTE

Thanks, I look forward to your results. I hope it works.