A coating composition comprising an oxidized α-olefin having 16 to 40 carbon atoms and one or more carboxylic acid or ester groups; a hydrocarbon-soluble ester-containing polymer having at least one branch of 10 to 36 carbon atoms and having a number average molecular weight of 5000 to 300,000; a carboxylic acid of at least 10 carbon atoms; a salt of an alkylarylsulfonic acid; an oil in an amount sufficient to dissolve said metal salt; and optionally, a volatile diluent, provides good rust protection.