Method for improving fluorocarbon elastomer seal compatibility

A method for improving compatibility of a fluorocarbon elastomer seal in an internal combustion engine containing fluorocarbon elastomer seals and operated with a lubricating oil composition comprising (a) a major amount of a base oil of lubricating viscosity;

• and (b) a dispersant mixture containing (i) a borated bissuccinimide, (ii) an ethylene carbonate post-treated bissuccinimide and (iii) a polysuccinimide, the method comprising (i) adding to the lubricating oil composition an effective amount of one or more fluorocarbon elastomer seal compatibility improving agents of the general formula Si—X4 or a hydrolysis product thereof, wherein each X is independently a hydroxyl-containing group, hydrocarbyloxy-containing group, acyloxy-containing group, amino-containing group, monoalkyl amino-containing group or dialkyl amino-containing group, and (ii) lubricating an internal combustion engine containing fluorocarbon elastomer seals, wherein the engine is in need of improved fluorocarbon elastomer seal compatibility with the lubricating oil composition.