Randall,

Yes, Redline DFC is good stuff. It's the same thing as 85. You should continue using it once you have started. (start off with one bottle of it in the fuel tank then 1/3 bottle thereafter) It acts by cleaning the combustion chambers, increases the cetane level, cleans injectors, adds lubricity to the fuel for the injection pump and other stuff I can't remember off hand. If you do a search, you will find alot of people recommend it including myself. I don't know what your concern is for using it.

Herb
'82 240D