Some time back I reported a steady, pulsing, thrumming which I felt in the steering wheel of my 86, 300E from about 45 to 55 MPH. The other day, after returning from the city, the red, oil warning light came on, I checked the oil level and it was down 1 1/2 litres(quarts to U.S. friends). Due to being busy I had not added any oil for 3,500 miles and it was down, alright. After adding the oil and driving back onto the highway, I noticed that the thrumming had disappeared and has not reappeared. Question: Could that have been due to the trochoid pump and that the engine oil level was a bit too low? If not, then I am baffled--still! All other checks came up ok!
Al Hardy on Vancouver Island