| abstract |
A heavy duty diesel engine lubricating oil composition comprising, or made by admixing: (A) a major amount of an oil of lubricating viscosity comprising at feast 35 mass % of a Group III basestock, based on the mass of the oil of lubricating viscosity, that contains at most 0.03 mass % of sulfur, based on the mass of the basestock, and that has a viscosity index of 120 or greater and has greater than or equal to 90 mass % saturates, based on the mass of said basestock; and (B) a minor amount of an additive composition comprising : (i) a detergent composition; and (ii) one or more other additives; wherein the oil composition has a cold cranking simulated viscosity, measured according to ASTM D2602, of less than 7000 mPa.s at -25°C and a sulfated ash, measured according to ASTM D874, of less than 1.35 mass %, based on the mass of the oil composition. The oil compositions provide improved piston cleanliness of a heavy duty diesel engine. |