Castrol 03849 GTX Diesel 15W-40 Motor Oil, 1 Gallon, 3 Pack Provides exceptional protection from piston deposits, oil thickening and valve train wear while minimizing engine sludge formulation Engineered to provide exceptional performance in engines operating under severe service conditions including towing and hauling under high temperatures Special viscosity improvers, anti-wear, anti-oxidant and detergent additives protect and maintain cleanliness in hot running, heavy diesel and heavy duty gasoline engines Applicable for on and off road heavy duty 4-stroke trucks, gasoline and diesel light trucks and passenger cars where API CJ-4, CI-4, CH-4, CG-4, CF-4, CF, SN are recommended Castrol recommends the use of Bosch oil filters