Lubricating oil compositions with engine corrosion protection

A method for improving corrosion resistance, while maintaining or improving fuel efficiency, in an engine or other mechanical component lubricated with a lubricating oil by using as the lubricating oil a formulated oil, said formulated oil having a composition comprising a lubricating oil base stock as a major component;

• and at least one friction modifier having an elemental composition comprising one or more of nitrogen (N), oxygen (O), and phosphorus (P), as a minor component;
• wherein said formulated oil has a corrosion factor, based on the elemental composition of the at least one friction modifier, of less than 500, as determined by the formula:
• 12900(N wt %)+3967(O wt %)−8524(P wt %)−250=corrosion factor
• and wherein corrosion resistance is improved and fuel efficiency is maintained or improved as compared to corrosion resistance and fuel efficiency achieved using a lubricating oil containing a minor component other than the at least one friction modifier, or having a corrosion factor of greater than 500.