| abstract |
A composition for reducing the copper-lead bearing corrosion of annengine that includes a major amount of an oil of lubrication viscosity and anminor amount of a corrosion-reducing additive comprisingn (A) a borated dispersant with a total base number of from 20 to 160 on annoil-free basis, selected from Mannich dispersants, succinimide dispersantsnor olefin-carboxylic/carboxylate dispersants; (B) a metal salt of a phosphorus acid; and (C) a metal overbased composition comprising at least one carboxylate,nphenate, or sulfonate wherein the metal is lithium, sodium, potassium, magnesium orncalcium, and (D) a borate ester. n The borated ester and borated dispersant provide from 20 to about 800 partsnper million (ppm) mass of boron in the composition. |