Abstract: The present invention is directed to a lubricating oil for use in engines subjected to sustained severe load conditions, said lubricating oil comprising a base oil, and an additive package comprising one or more neutral/low TBN or a mixture of neutral/low TBN, and overbased/high TBN alkali or alkaline earth metal alkyl sulfonates, alkyl phenates, alkyl salicylates, an antioxidant selected from the group consisting of glycerine derivatives comprising glycerine grafted with a hindered phenol, hindered phenolic containing a thioether group, and mixtures thereof, optionally an additional conventional antioxidant and/or an organomolybdenum compound, and other additives, and to a method for enhancing the deposit formation resistance of a lubricating oil used in engines operated under sustained severe load comprising the addition to the lubricant of the aforesaid additive package.

Abstract: Engine lubricating oils used under sustained high load conditions, such as high speed diesel or stationary natural gas engines, can have their deposit control properties enhanced by the addition to such engine oils of a minor amount of one or more neutral/low TBN or mixture of neutral/low TBN and overbased/high TBN alkali and alkaline earth metal salts of alkyl salicylates, or alkyl phenolate, a minor amount of one or more of an organo molybdenum complex in an amount sufficient to provide 25 wt. ppm to 2000 wt. ppm elemental molybdenum in the final lubricant composition.

Abstract: A long life lubricating oil, as evidenced by a reduction in oil thickening, oxidation, nitration and low deposit-forming tendency, comprises a major amount of a base oil of lubricating viscosity and a minor amount of a mixture of neutral and overbased metallic detergents and at least one trinuclear molybdenum compound.

Abstract: A natural gas engine oil composition with enhanced resistance to oxidation, nitration and viscosity increase comprising: an oil basestock; neutral and overbased metallic detergents; an antioxidant comprising an alkylthiocarbamoyl compound or a mixture of an alkylthiocarbamoyl compound and an ashless, non-sulfur containing, hindered phenol; and a zinc dihydrocarbyl dithiophosphate in an amount sufficient to provide the composition with from 250 to 450 wppm phosphorus.