Abstract: A lubricant composition is described, particularly for engine oils, comprising a base oil of viscosity from 3 to 26 cSt (mm2/s) at 100° C. and an antiwear additive combination comprising (a) an oil soluble or oil dispersible phosphorus-free organo-molybdenum compound, (b) an ashless, sulfur-containing organo-phosphorus compound, and optionally (c) a zinc thiophosphate compound selected from one or more of zinc dialkyldithiophosphate, zinc diaiyldithiophosphate, zinc alkylaiyldithiophosphate and zinc arylalkyldithiophosphate. The molybdenum compound may be a carbamate, e.g., MoDTC but is preferably nitrogen-free, e.g., a carboxylate.

Abstract: A lubricant composition e.g. for engine oils comprises (i) a base oil, (ii) an antiwear additive combination comprising (a) an organo-molybdenum compound and (b) an asoless organo-phospoorus compound, and (iii) an antioxidant additive combination comprising (d) an aminic antioxidant and (e) a phenolic antioxidant, the weight ratio of aminic antioxidant to phenolic antioxidant being greater than 1:1, preferably from 1.5:1 to 20:1. The antiwear additive combination (ii) may further comprise (c) a zinc thiophosphate compound selected from zinc dialkyldithiophosphate, zinc diaryldithiophosphate and zinc alkylaryldithiophosphate and zinc arylalkyldithiopoosphate and mixtures thereof.