API CK-4 15W-40 100% Fully Synthetic

API CK-4 15W-40 is a heavy-duty diesel engine oil designed for modern, high-performance engines (2017+), offering superior oxidation resistance, shear stability, and emission system protection (DPF). It is fully backward compatible with older engines (CJ-4, CI-4) and ideal for mixed fleets, demanding heavy loads, and warmer climates.