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 (I) and/or formula (II):


In formula (I), each Ar independently represents an aromatic moiety having 0 to 3 substituents selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, aryloxy, aryloxyalkyl, hydroxy, hydroxyalkyl, 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 -OR 1" or a moiety of the formula H(O(CR 1 2 ) n ) y X-, wherein X is selected from the group consisting of (CR 1' 2 ) z , O and S; R 1 and R 1' are each independently selected from H, C 1 to C 6 alkyl and aryl; R 1" is selected from C 1 to C 100 alkyl and aryl; z is 1 to 10; n is 0 to 10 when X is (CR 1' 2 ) z , and 2 to 10 when X is O or S; and y is 1 to 30; each a is independently 0 to 3, with the proviso that at least one Ar moiety bears at least one group Y; and m is 1 to 100. 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(CR 2 2 ) n' ) y' X'-, wherein X' is selected from the group consisting of (CR 2' 2 ) z' , O and S; R 2 and R 2' are each independently selected from H, C 1 to C 6 alkyl and aryl; z' is 1 to 10; n' is 0 to 10 when X' is (CR 2' 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.