I have used Mobil 1 Turbo Diesel Truck 5w-40 in our Land Rover Discovery for over 10 years. The engine runs as new at 144K miles (unusual for the LR engines) with none of the usual rear main seal leaks due to worn main bearings. Flat tappet cam. When I had the head gaskets done the guys at the shop were impressed enough with the engine state they offered to buy the truck.
Also, it passes emissions tests still with the original cats.
Also, it passes emissions tests still with the original cats.