A lubricant composition comprising a major amount of baseoil lubricant and
a minor amount of lubricant additive. The lubricant additive includes (a)
a dispersant containing at least one member selected from
hydrocarbyl-substituted succinimides, hydrocarbyl-substituted amines, and
Mannich base adducts derived from hydrocarbyl-substituted phenols
condensed with an aldehyde and an amine, and (b) a viscosity index
improver that includes a substantially linear block copolymer having a
number average molecular weight as determined by gel permeation
chromatography ranging from about 50,000 to about 250,000. The block
copolymer is derived from a conjugated diene monomer containing no less
than 5 carbon atoms and a monoalkenylarene monomer, wherein the block
copolymer has an aromatic content ranging from about 10 wt. % to about 50
wt. % and an olefinic unsaturation ranging from about 0.5 wt. % to about
5 wt. %.