Lubricating oil compositions

A method comprising the step of operating an internal combustion engine with a lubricating oil composition comprising

• (a) a major amount of an oil of lubricating viscosity
• (b) an overbased metal salt of an alkyl-substituted phenate detergent, wherein the alkyl group is derived from an isomerized normal alpha olefin having from about 10 to about 40 carbon atoms per molecule and having an isomerization level (I) of the normal alpha olefin of from about 0.1 to about 0.4,
• (c) one or more magnesium-containing detergents having about 100 to about 2000 ppm of magnesium, based on the total weight of the lubricating oil composition;
• (d) one or more zinc dialkyl dithiophosphate compounds, wherein at least one zinc dialkyl dithiophosphate is derived from a primary alcohol;
• and
• (e) one or more zinc dialkyl dithiophosphate compounds derived from a secondary alcohol,
• wherein the molar ratio of the primary alcohol of the one or more zinc dialkyl dithiophosphate compounds derived from a primary alcohol to the secondary alcohol of the one or more zinc dialkyl dithiophosphate compounds derived from a secondary alcohol is from 80:20 to 20:80.