Engine oil having dispersant and aldehyde/epoxide for improved seal performance, sludge and deposit performance

A lubricating composition for internal combustion engines, suitable for providing reduced seal deterioration and reduced sludge production, said lubricating composition comprising

• a major amount of an oil of lubrication viscosity and a minor amount of an admixture consisting of
• (A) a nitrogen-containing dispersant with a total base number of from 30 to 160 on an oil-free basis, said nitrogen-containing dispersant being selected from the group consisting of (1) Mannich reaction products of at least one phenol containing at least one aliphatic substituent with formaldehyde and an amino compound and (2) reaction products of hydrocarbyl-substituted succinic acylating agents, said hydrocarbyl group having a number average molecular weight of at least about 300, and at least one of (a) ammonia or (b) an amine;
• and
• (B) a sludge preventing/seal protecting additive of at least one aromatic aldehyde, or epoxide containing a terminal oxirane ring, or mixtures thereof;
• provided that components (A) and (B) are mixed together followed by addition of other components.