| abstract |
An object of the present invention is to suppress generation of sludge, improve turbo coking resistance, and ensure long drain characteristics. The lubricating oil composition for a 4-cycle engine of the present invention comprises a base oil (A) and a polyolefin (B) having a structural unit derived from at least isobutene and having a number average molecular weight of 500 to 10,000. 0.5 to 10% by mass, and the sulfated ash content exceeds 0.7% by mass and is 1.2% by mass or less. [Selection figure] None |