Lubricating oil compositions for biodiesel fueled engines

A method for improving the resistance to oxidation of lubricating oils used to lubricate engines run on biodiesel fuels comprising adding to the lubricating oil an additive amount of a combination of one or more detergents selected from alkaline earth metal salicylate, and hydrocarbyl salicylate, and two anti-oxidants, wherein the two antioxidants are a 50:50 mixture of a hindered phenolic anti-oxidant and a hindered aminic anti-oxidant wherein the weight ratio (active ingredient) of detergent to anti-oxidant is about 1.5 to 1, wherein the one or more detergents and the two anti-oxidants are premixed prior to being added to the lubricating oil and wherein the premix is formed by weighing and adding sequentially to a stirred heat vessel at about 60 deg. C. the one or more detergents and the two anti-oxidants, and mixing in said stirred heat vessel for a time of about 90 minutes, wherein the lubricating oil is a methyl ester and wherein the premix of detergent and anti-oxidant is added to the lubricating oil in a combined amount of about 0.5 wt % (active ingredient).