2004 C240, Display says 'Engine Oil Level - Visit Workshop'
 

Help! Every morning before I start/run my 2004 C240 4Matic, I usually check the engine oil level through the dash. Last week and continuing this week, when I do this each morning, the info tells me to 'Observe Waiting Period' although the engine is cold & car was parked overnight in my driveway. When I go through the sequence on the dash, it tells me I have '1 Malfunction' - 'Engine Oil Level, Visit Workshop'. I just did an oil change 2 weeks ago and I'm sure the oil level is good (7-3/4 quarts of synthetic Mobil 1, 5W-30 & new Mann fleece oil filter). The engine doesn't burn oil and there is no leak underneath (the engine). Additionally, I use the dipstick from my 2008 C300 (a little long for the C240) to make sure I have enough oil on the engine which I do. After starting and warming up the engine, I shut it off and observe 30+ minutes waiting period before I recheck the oil level again through the dash. This time the malunction is no longer displayed (No Malfunction) and when checking the oil level it tells me it's 'OK'. Am I having an intermittent Oil Sender malfunction or something I should take care of right away? Appreciate the assistance.

Is that the amount of oil stated in the manual? If so you have put in a quart too much probably. The manual figure is for a dry engine, not for oil changes. On my car the manual says the capacity is 6.5 qts but it takes 5.7. So the sensor might be reporting too much oil, which can be as bad as too little. I am not sure how you can use a dipstick from a different car to tell you anything. I could be wrong however...

Josemin, based on your description of the recent oil change I concur that you likely overfilled the engine. If you have a suction device remove 1/2 quart and check the dash display.

Although the Owner's Manual for our 124 cars specifies 8 quarts, typically 7 quarts will put the level midway between the "full" and "add" dipstick marks.

2004 C240, Display says 'Engine Oil Level - Visit Workshop'
 

Thanks for your replies. You could be right on the excess amount of oil - which I can drain some or reduce with no problem at all. However, ever since I've been doing the oil changes (after the warranty expired), I've been putting in the same amount of oil all along. Every time I check the Dash on the oil level after each oil change, it always tells me Oil Level 'OK'. So, I always assumed the amount of oil I put in is correct. Besides, during the Dash info check, it will tell you if you have excess oil or requires additional oil to the engine - neither was the case. The user manual also tells you that there could be 'water' on the oil when you get this malfunction - which is very, very unlikely after having done the oil change only 2 weeks ago. Perhaps, my next move is to have diagnostic done to see if there are any error codes present. Additional responses/replies from our experienced members will be appreciated, especially from our experienced MB Techs out there.

Crying wolf
 

Having owned a W203 C320 from 2001 through 2007, I have seen lots of these false alarms and have learned to ignore them. The first time I did think about a coolant leak into the crankcase which proved to be wrong,of course. The V-6s just don't have all those designed in defects the previous engines were famous for.

There is a software change (dealer's laptop) that alters the oil level sensor parameters if it's worth a trip to the dealer for an out of warranty car.

BTW, after more warranty repairs on that accursed '01 C320 than I could count, my 2008 C300 (three years old in October) has been the most trouble free car I've ever owned. And as a MB owner since 1973, I am still not used to not making those monthly dealer repair visits.

I don't think this is a false alarm anymore. I am now convince there is a malfunction. Logic indicates the 'Oil Level Sender' as the likely culprit (I could be wrong, also). The malfunction is now happening regularly everytime I start/run the car. While driving, '1 Malfunction' will get displayed on the dash and if you check it, it will tell you 'Engine Oil Lever - Visit Workshop'. The '1 Malfunction' will reset/go away when you shut down the engine but it will come back up again as soon as you restart/run the car. Also, I had someone check the Fault Codes using a OBDII reader but there were 'None'. Instead of going to the stealership for a Star Diagnostic, I thought my $$ will be well spent with a new Oil Level Sender (about $90). Besides, it's worth a try. Then again, I could be wrong - but still worth a try. I was told the oil level sensor is located by the oil pan or just above it. Anybody out there who can pinpoint me to the exact location and perhaps provide detailed installation instruction on replaing this unit?? This is for a 2004 C240 4Matic with a 2.6 Liter gas engine. Appreciate all replies and assistance(s).

Josemin, typically the oil level sender is mounted on the side of the oil pan. Not sure of the exact configuration on your engine. Best to change the oil level sender when changing oil and the oil pan is drained.

Thanks, Fred. I'll check the sensor location as soon as my part arrives. Good call for the oil change. I'll drain the engine oil and do another oil change during the sensor replacement work. I'll put in fresh oil and filter after the work. I'll post an update when the work is done.

Finally did the work on my C240. Prior to doing the work, I had a Star Diagnostic done and sure enough, the problem indicated a malfunctioning oil level sensor. Parts I purchased included the OEM oil level sensor, MB RTV sealant and yes, a new lower oil pan. The old oil pan was a pain to remove. The original sealant was too tough to separate the lower oil pan to the top pan, so I wind up forcing it down with a metal tool on a reinforced tab (using the new pan as a model to look inside and find where to pull), warped/ruined the old oil pan in the process (I'm just glad I bought a new lower pan). Also, I had to removed the front stabilizer bar in the process to make room for the pan to come out and the reinstallation of the new pan. Replacing the oil level sensor, which is inside the engine (right side) by the top oil pan, was a little pain also but straigth-forward. I decided to let the RTV cure overnight (as advised by a MB Tech) before filling the engine with new oil. Yes, I had to do an oil and filter change as well. Following morning I filled up the engine with the recommended amount of new oil and filter change. Now, I don't get a 'malfunction' on the dash readout anymore. To my understanding (this forum can correct me if I'm wrong), the work I just did was not a required maintenance work since the oil level sensor just gives you indication of oil condition, amount, etc. It's just what I call an 'informational' sensor. I can surely live with the 'malfunction' readout but was a nuisance and distraction. Surely, I can say I'm glad I did it! BTW, MB stealership said the work is about 5 hours at $125/hr + parts - if I had them do it for me. My total cost is over $240 on parts + five hours of work. BYI, you'll need a lift also to do this work or it would be a real pain with jacks.