Howdy folks, just bought a 87 300D turbo a few weeks ago with 148k on it, after a couple year hiatus from owning any benzs. The previous 2 owners had been using 0w-40 Mobil 1 engine oil, and mobil 1 in the rest of the gearboxes as well. It is time to change the oil and I looked at the bottle of 0w-40 mobil 1 and I don't feel it is a real diesel oil although it does have a CF clasification on the back. I would feel more at ease with Mobil 1's 5w-40 because it actually says it is for use in diesel engines. I got all of the service records with the car and even the very dealership where the car was bought brand new wasn't consistent with what they put in as oil, sometimes it was Penzzoil or Castrol but it was 15w-40 which is widely recognized as diesel oil. Anyhow I'm not sure its worth $7 a quart for the Mobil 1. I have a Dodge Ram Cummins with 262k on the clock and have used Cummins Valvoline Premium Blue 15w-40 in it year around since new with 0 problems. I was just going to use this in the MB as well so as to simplify things, then the local NAPA store starts carrying this Lubro-Moly oil and diesel additive. Can anybody advise on this stuff or make recomendations on what I should use.