Lubricating oil composition

A lubricating oil composition having a total base number of more than 15 mg KOH/g, as determined by ASTM D2896, and including at least 40 mass % of an oil of lubricating viscosity; at least one detergent; and at least one compound of the formula (II): In formula (II), each Ar independently represents an aromatic moiety having 0 to 3 substituents selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, hydroxy, hydroxyalkyl, acyloxy, acyloxyalkyl, aryloxy, aryloxy alkyl, halo and combinations thereof; each L is independently a linking moiety comprising a carbon-carbon single bond or a linking group; each Y' is independently a moiety of the formula Z(O(CR2)n)yX-, wherein X is selected from the group consisting of (CR'2)z, O and S; R and R' are each independently selected from H, C1 to C6 alkyl and aryl; z is 1 to 10; n is 0 to 10 when X is (CR'2)z, and 2 to 10 when X is O or S; y is 1 to 30; Z is H, an acyl group, an alkyl group or an aryl group; each a is independently 0 to 3, with the proviso that at least one Ar moiety bears at least one group Y' in which Z is not H; and m is 1 to 100.