PURPOSE: Provided is a lubricant composition suitable for use in automotive engines, especially internal combustion engines. CONSTITUTION: Lubricant compositions are suitable for use in automatic engines, especially internal combustion engines, the lubricant having a kinematic viscosity at 100C of less than 12.5 mm2/s and a high temperature, high shear dynamic viscosity (i.e. at a temperature of 150C and a shear rate of 106/s) of at least 2.9 mPa.s, and comprising (a) 70 to 99.5 wt.% of a base oil, preferably a mixture of poly-alpha-olefin and ester, having a kinematic viscosity at 100C of 2 to 8 mm2/s and a viscosity index of at least 120,and (b) 0.5 to 3 wt.% of an alkenylarene-conjugated diene copolymer, preferably styrene/butadiene copolymer, as a viscosity index improver. The lubricant provides an improvement in fuel economy performance whilst maintaining effective lubrication of the engine under operating conditions.
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