Patent ID: 7189682

Claim:
A composition suitable for use as a functional fluid in a variety of climatic conditions, comprising the following components: (a) an oil of lubricating viscosity; (b) about 4 to about 12 percent by weight of a viscosity modifier having a weight average molecular weight of about 10,000 to about 60,000; and (c) about 1 to about 5 percent by weight of a second viscosity modifier, having a weight average molecular weight greater than that of component (b) and being about 100,000 to about 200,000; wherein (b) is a polyacrylate or polymethacrylate and (c) is a polymer comprising vinyl aromatic units and esterified carboxyl-containing units, and wherein the total amount of component (b) and component (c) is 5 to 15 percent by weight.