Viscosity control method

Abstract

The present invention provides a method of lubricating an internal combustion engine comprising at least one of the crankcase, a gear and a wet clutch, the method comprising the crankcase, a gear and a wet clutch, supplying a lubricating composition comprising a comprising the step of: an oil of (a) lubricating viscosity; a viscosity modifier having a number average molecular weight of and (b) 1000~75,000, wherein said lubricating composition, of XW-Y It has a SAE viscosity grade, wherein, X is 0 to 20 and Y is about 20-50; and, wherein the lubricating composition is 0.12 wt% or less hydrocarbyl dithiophosphate having a phosphorus content of from acid metal.