Lubricant composition for reduced engine sludge

A lubricant composition effective to reduce engine sludge, the lubricant composition comprising

• a base oil of lubricating viscosity;
• nitrogen provided by a dispersant system and an antioxidant system;
• about 1 to about 8 weight percent of the dispersant system including a first hydrocarbyl substituted succinimide dispersant obtainable by reacting a hydrocarbyl substituted acylating agent with a nitrogen source wherein the hydrocarbyl substituent of the first dispersant has a number average molecular weight of at least about 1900 and a second hydrocarbyl substituted succinimide dispersant obtainable by reacting a hydrocarbyl substituted acylating agent with a nitrogen source wherein the hydrocarbyl substituent of the second dispersant has a number average molecular weight less than 1900;
• about 0.3 to about 4 weight percent of the antioxidant system including at least an alkylated diphenyl aminic antioxidant and a hindered phenolic antioxidant;
• a weight ratio of nitrogen provided by the dispersant system to total nitrogen in the lubricant composition of about 0.6:1 to about 0.8:1;
• at least about 75% of the nitrogen provided by the dispersant system is a primary or secondary nitrogen and not post-reacted;
• a weight ratio of nitrogen provided by the aminic antioxidant of the antioxidant system to the total nitrogen in the lubricant composition of about 0.15:1 to about 0.4:1
• a weight ratio of nitrogen provided by the dispersant system to nitrogen provided by the aminic antioxidant of about 1.8:1 to about 5.3:1;
• and
• wherein the lubricant composition exhibits an average engine sludge of about 7 to about 10 merits pursuant to CEC L-107-19.