A novel crankcase dispersant reaction product having fused therein an antioxidant moiety whereby the dispersant reaction product can function as an antioxidant while retaining at least two structural domains, one being a polar domain for association with sludge and a hydrocarbyl domain for oil solubility, so that the dispersant can function as a chemical agent to suspend sludge and prevent agglomeration of sludge precursors and soot so the latter can be readily removed from the system, such as by filtering, instead of being deleteriously deposited on internal engine components, as well as lubricant compositions incorporating such novel dispersant and, for instance, engines lubricated with such lubricant compositions.