83W123DT,

I drive a 300SD and 300SDL now. I have had 180D,190D,200D 220D and 240D in the past. I have logged about 1/2 million miles on MB Diesels.

Anything you pour into the fuel tank other than Diesel fuel, I consider an additive. I do use alcohol (Drygas) once in a while to remove moisture.

I wouldn't say that DP is the same as a fuel filter. A filter blocks dirt from getting into the injection system whereas DP is a cleaner than is supposed to remove contaminates from the injectors.

P E H