Patent ID: 8575080

Claim:
A method of lubricating a diesel engine with a lubricating oil composition, the method comprising providing the lubricating oil to the diesel engine, and wherein the lubricating oil comprises a lubricating base oil selected from the group consisting of a hydrotreated mineral oil and a synthetic oil; and: component (A): 5 to 20% by mass, based on the total amount of the composition, of a mono-based succinimide compound having an alkenyl group or an alkyl group of a number average molecular weight of 130 to 250 or a boronic compound thereof, and component (B): 2 to 10% by mass, based on the total amount of the composition, of a succinimide compound having an alkenyl group of a number average molecular weight of 800 to 3,500, wherein the lubricating oil composition comprises a boron content of 100 ppm by mass or more and has a sulfated ashes content of 0.8% by mass or less.