A lubricant composition comprising: (a) an oil of lubricating viscosity (b) at least two nitrogen-containing materials, comprising at least one each of: (i) 0.2 to 3 percent by weight in the lubricant composition of at least one amide represented by the formula R 3 C NR 1 R 2 wherein R 1 and R 2 are each independently hydrocarbyl groups of at least 6 carbon atoms and R 3 is a hydroxyalkyl group of 1 to 6 carbon atoms or a group formed by the condensation of said hydroxyalkyl group, through a hydroxyl group thereof, with an acylating agent and (ii) 0.03 to 0.5 percent by weight in the lubricant composition of at least one tertiary amine being represented by the formula R 4 R 5 NR 6 wherein R 4 and R 5 are each independently alkyl groups of at least 6 carbon atoms and R 6 is a polyhydroxy-containing alkyl group or a polyhydroxy-containing alkoxyalkyl group; (c) 2 to 5 percent by weight of a functionalized dispersant component, comprising one or more dispersants, treated with (i) 2,5-dimercapto-1,3,4-thiadiazole or a hydrocarbyl-substituted 2,5-di-mercapto-1,3,4-thiadiazole and (ii) a borating agent, and optionally (iii) an inorganic phosphorus compound, and optionally (iv) an aromatic 1,3-dicarboxylic acid or 1,4-dicarboxylic acid, or a reactive equivalent thereof; wherein the dispersant of component (c) comprises at least one succinimide dispersant; (d) 0.22 to 2 weight percent of at least one di-C3-C6 alkyl phosphite; and (e) 0.1 to 1 weight percent of a trialkyl borate, the alkyl groups of which each contain 4 to 12 carbon atoms. (a) an oil of lubricating viscosity (b) at least two nitrogen-containing materials, comprising at least one each of: (i) 0.2 to 3 percent by weight in the lubricant composition of at least one amide represented by the formula R 3 C NR 1 R 2 wherein R 1 and R 2 are each independently hydrocarbyl groups of at least 6 carbon atoms and R 3 is a hydroxyalkyl group of 1 to 6 carbon atoms or a group formed by the condensation of said hydroxyalkyl group, through a hydroxyl group thereof, with an acylating agent and (ii) 0.03 to 0.5 percent by weight in the lubricant composition of at least one tertiary amine being represented by the formula R 4 R 5 NR 6 wherein R 4 and R 5 are each independently alkyl groups of at least 6 carbon atoms and R 6 is a polyhydroxy-containing alkyl group or a polyhydroxy-containing alkoxyalkyl group; (i) 0.2 to 3 percent by weight in the lubricant composition of at least one amide represented by the formula R 3 C NR 1 R 2 wherein R 1 and R 2 are each independently hydrocarbyl groups of at least 6 carbon atoms and R 3 is a hydroxyalkyl group of 1 to 6 carbon atoms or a group formed by the condensation of said hydroxyalkyl group, through a hydroxyl group thereof, with an acylating agent and (ii) 0.03 to 0.5 percent by weight in the lubricant composition of at least one tertiary amine being represented by the formula R 4 R 5 NR 6 wherein R 4 and R 5 are each independently alkyl groups of at least 6 carbon atoms and R 6 is a polyhydroxy-containing alkyl group or a polyhydroxy-containing alkoxyalkyl group; (c) 2 to 5 percent by weight of a functionalized dispersant component, comprising one or more dispersants, treated with (i) 2,5-dimercapto-1,3,4-thiadiazole or a hydrocarbyl-substituted 2,5-di-mercapto-1,3,4-thiadiazole and (ii) a borating agent, and optionally (iii) an inorganic phosphorus compound, and optionally (iv) an aromatic 1,3-dicarboxylic acid or 1,4-dicarboxylic acid, or a reactive equivalent thereof; wherein the dispersant of component (c) comprises at least one succinimide dispersant; (i) 2,5-dimercapto-1,3,4-thiadiazole or a hydrocarbyl-substituted 2,5-di-mercapto-1,3,4-thiadiazole and (ii) a borating agent, and optionally (iii) an inorganic phosphorus compound, and optionally (iv) an aromatic 1,3-dicarboxylic acid or 1,4-dicarboxylic acid, or a reactive equivalent thereof; (d) 0.22 to 2 weight percent of at least one di-C3-C6 alkyl phosphite; and (e) 0.1 to 1 weight percent of a trialkyl borate, the alkyl groups of which each contain 4 to 12 carbon atoms.