Product Details: Update your semi truck with powerful engine oil, with the Castrol CRB Multi SAE 15W-40 CK-4 Heavy Duty Diesel Engine Oil that ensures you're Ready for the Road Ahead™. Due to its ability to protect against wear, deposits, and oil thickening, this replacement oil is the ideal solution for a variety of commercial vehicles. Formulated with better shear stability and protection against viscosity loss. FleetPride is your First Click in Heavy Duty®.