Multigrade lubricating compositions containing no viscosity modifier

A multigrade crankcase lubricating oil substantially shear stable in the Kurt-Orbahn test and exhibiting multigrade viscosity requirements in the absence of a high molecular weight viscosity modifier having a molecular weight (Mn) above 7000, which oil comprises;

• a) basestock, and
• b) 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 have an Mn of from 500 to 7000 and has >30% of terminal vinylidene unsaturation;
• wherein said crankcase lubricating oil is 15W30, 15W40, 10W30, 10W40, 5W20 or 5W30 multigrade oil
• in which the detergent inhibitor package contributes at least 5 mm.sup.2/ s of the initial kV100.degree. C. of the lubricating oil.