This is a built 6.8L Cummins engine from Freedom Racing Engines. 11k miles on the engine and 3200 on the oil. Makes about 1400hp at the crank. This truck uses the power and sees plenty of hard use. Oil is 20w-50 from Penngrade link to oil here Due to availability, I switched to Amsoil Dominator 20w-50 on this oil change. Worried about the possible coolant issues in the oil and I'm considering running water instead of coolant for the summer time.