Lubricating oil compositions and methods of their use are provided herein. A lubricating oil composition as described herein includes a major amount of an oil of lubricating viscosity, an amine-functionalized olefin copolymer dispersant viscosity index improver in an amount of from about 1.5 wt. % to 2.0 wt. % based on the weight of the lubricating oil composition, and a dispersant. The amine-functionalized olefin copolymer dispersant viscosity index improver includes a reaction product of an acylated olefin copolymer and a polyamine. The dispersant includes reaction product of components (A) a hydrocarbyl-dicarboxylic acid or anhydride having a number average molecular weight of from about 500 to about 5000 and (B) at least one polyamine, wherein the reaction product is post-treated with (C) an aromatic carboxylic acid, an aromatic polycarboxylic acid, or an aromatic anhydride, wherein all carboxylic acid or anhydride groups are attached directly to an aromatic ring, and/or (D) a non-aromatic dicarboxylic acid or anhydride having a number average molecular weight of less than about 500.