Abstract: Lubricating oil compositions are provided which comprise: (A) a major amount of oil of lubricating viscosity, and (B) an effective amount dissolved therein of each of (1) a zinc primary dihydrocarbyl dithiophosphate; (2) a mixture of (a) certain dimeric acids and (b) the reaction product of a monocarboxylic acid, certain polyalkylene polyamines and an alkenyl succinic anhydride; and (3) a substantially neutral zinc salt of a dihydrocarbyl sulfonic acid. These lubricating oil compositions are useful as functional fluids in a variety of systems as coolants, hydraulic fluids, turbine oils, spindle oils and the like.