NORTH 69 SAE 15W-40 CK-4 Heavy Duty Engine oil Formula for superior heavy duty, Excellent wear protection and friction reduction across wide range of operating conditions. High detergency allows extended drain intervals and provides increased cleanliness. Improved fuel economy and ring seal for more power. Superior high temperature stability and oxidation resistance increases lubrication of hot metal compared to others. High natural viscosity index provides thicker oil film in bearings and cams. Less evaporation for improved efficiency and ring seal. All products are completely compatible with other conventional and motor oils.