| abstract |
A lubricating oil composition excellent in friction -reducing effect and long-drain performance (leading to a longer period of service) and particularly suitable for internal combustion engines, which comprises a lube base oil, a specific phosphorus compound in an amount of 0.005 to 0.5 % by mass based on the whole of the composition in terms of phosphorus, and at least one additive selected from the group consisting of (C) metallic detergents, (D) ashless dispersants, and (E) antioxidants, and further contains (F) a sulfur-containing organomolybdenum complex and (G) an ashless friction modifier and which satisfies prescribed requirements and has a sulfated ash content not exceeding a specified level. |