I know it’s not a diesel….but I used it in my 98’ Silverado with 425k that’s had pretty good maintenance over the years, and after 20 minutes of idle, the brown oil came out almost pitch black. Wasn’t a miracle fix for anything, but I’d say it did remove some old sludge from some nooks and crannies in my old 350
Pros: removed some old sludge
Cons: wasn't a miracle fix
Vehicle:
Chevrolet Silverado
Mileage: 425000 km
