KLONDIKE SAE 15W-40 CK-4 Full Synthetic Heavy Duty Engine Oil is specifically engineered for engines operating under severe service in a wide range of climatic conditions and ambient temperatures. An ideal mixed fleet engine oil designed for naturally aspirated and turbocharged heavy duty diesel engines in mobile and stationary equipment where the API CK-4 service category and SAE 15W-40 viscosity grade is specified. Advanced API CK-4 additive technology is fully backwards compatible with, and replaces, service categories CJ-4, CI-4 Plus, and previous. KLONDIKE SAE 15W-40 CK-4 Full Synthetic Heavy Duty Engine Oil contains field proven additive technology which delivers maximum control on engine wear, outstanding engine cleanliness, and high TBN and viscosity retention for outstanding lubricant life and maximum engine durability. Metal anti-wear protection exceeds API CK-4 standards and tough OEM specifications.