MULTIGRADE LUBRICATING COMPOSITIONS CONTAINING NO VISCOSITY MODIFIER
This invention relates to shear stable multigrade oils for crankcase lubrication of gasoline and diesel engines which oils are substantially free of viscosity modifier additives and comprise a detergent inhibitor package of lubricating oil additives, which package includes an ashless dispersant comprising an oil soluble polymeric hydrocarbon backbone having functional groups in which the hydrocarbon backbone is derived from an ethylene alpha-olefin (EAO) copolymer or alpha-olefin homo- or copolymer an <o>M</o>n of from 500 to 7000. Such multigrade crankcase oils without viscosity modifiers are more economical and may provide better diesel performance and seal compatibility. The oils are also substantially shear stable and may be used in turbocharged engines and racing engines, with reduced mechanical breakdown of the oil.