looking at the OM642... and found this eye opener article, it is very long, so I am not going to paste the whole article. Ill make a word copy if it ever goes into oblivion, so we have a back up. And yes it mentions ZDDP
http://www.stephensservice.com/bluetec- ... sproblems/
Most people are finding this website after they’ve had a problem with their Mercedes-Benz BlueTec diesel. Other people find it as they research a new Sprinter. Still others have found the link on an owner’s forum. The article was originally written as a way to explain the BlueTec diesel to my local customers. As time passed I began to hear from BlueTec owners all over the world. I’ve learned a lot from their thousands of stories. If I tried to cover them all, this article would be impossible to read. However, those stories constantly motivate me to search for a better and more concise way of conveying what I’ve learned about the Mercedes-Benz BlueTec diesel. I worked for Mercedes-Benz as a Mechanic, Shop Foreman, Instructor, and a Service Manager for 50 years. I retired last year. In my opinion a BlueTec diesel is the most complicated engine Mercedes-Benz ever built.