| abstract |
A lubricating oil composition is provided as an engine oil for an internal combustion engine employing heat management. The composition includes (A) a base oil having 100° C. kinematic viscosity of 3.0 to 5.0 mm 2 /s, (B) a boronated succinimide in an amount of 0.007 mass percent or more as boron and in an amount of 5 mass percent or less as the succinimide ashless dispersant, based on total mass of the composition, (C) a phenol-based antioxidant in an amount of 0.5 mass percent or more, and (D) a viscosity index improver having a ratio of weight average molecular weight and PSSI of 1.2×104 or greater in an amount of 0.1 to 5 percent by mass. The composition has a 150° C. HTHS viscosity of 2.0 to 2.8 mPa·s, a 100° C. HTHS viscosity of 4.8 mPa·s or lower and a viscosity index of 180 or greater. |