Abstract: Disclosed herein is lubricating oil composition for providing enhanced piston cleanliness in an internal combustion engine. The lubricating oil composition includes (a) greater than 65 wt. %, based on the total weight of the lubricating oil composition, of a base oil component having a Kv at 100° C. of about 3.5 to about 4.5 cSt; (b) about 3.0 wt. % to about 10 wt. %, based on the total weight of the lubricating oil composition, of at least one Mannich reaction product prepared by the condensation of a polyisobutyl-substituted hydroxyaromatic compound, wherein the polyisobutyl group is derived from polyisobutene containing at least about 70 wt. % methylvinylidene isomer and has a number average molecular weight of from about 400 to about 2,500, an aldehyde, an amino acid or ester derivative thereof, and an alkali metal base; and (c) at least one ashless dispersant other than component (b); wherein the lubricating oil composition has a sulfur content of less than or equal to about 0.30 wt.