[irastock]

The same thing happened to me on my 2005 E320 CDI. I bought it out of state from an independent dealer and started driving it home on the interstate. I got the red overfill warning and had to find the nearest MB dealer. Many non-MB mechanics have no idea how to correctly measure the oil level in these engines since there is not a dipstick. (I have even had MB mechanics overfill it.) To make sure, I bought a dipstick to measure it myself. As Photodude says, you can Google for the manual as well as for a dipstick. Since the dipsticks out there measure in mm, I use the attached oil level chart to see what the measurement should be. It shows how many liters it is over- or under-filled depending upon the measurement. If you are in the US, the commas are periods for us. Hope this helps.

 

[irastock]

By the way, the motor in the 2005 E320 CDI inline 6 is known as an OM648. This will help you with your Google searches on dipsticks, etc.