FWIW, diesel purge did jack diddly squat for my SDL's engine. Some nastiness came out, sure, but it didn't do anything to fix its running problems. Mine was all mechanical wear to the delivery valve faces. Resolving that problem resolved the running issues. Diesel Purge did mask the problem (silent and smooth) when running on it, but back on diesel and it was right back to shake, rattle, and roll.

Your mileage may vary. I'm not a huge fan or proponent of any "cure in a bottle".

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)