Patent ID: 8026199

Claim:
A lubricating oil composition comprising: a lubricating base oil containing, on the basis of the total mass thereof, 40 percent by mass or more of base oil (X) with a kinematic viscosity at 100° C. of 1 to 8 mm 2 /s, a pour point of −15° C. or lower, an aniline point of 100° C. or higher, and a viscosity index of 100 to 135, the saturates of the base oil containing 40 to 57 percent by mass of paraffins and 43 to 60 percent by mass of naphthenes, wherein a mass ratio of one ring naphthenes to two to six ring naphthenes is 0.78 or less, the ratio of the tertiary carbon in the whole carbon constituting the base oil being 6.3 percent or greater; (A) (a) a non-dispersant type olefin (co)polymer viscosity index improver in such an amount that the viscosity index of the composition is 150 or greater, and at least one type of additive selected from the group consisting of: (B) a phosphorus-containing anti-wear agent; (C) a metallic detergent: (D) an ashless anti-oxidant; and (E) an organic molybdenum compound.