Lubricating oil compositions

A method of reducing wear of metal parts in a compression ignition diesel engine, which comprises lubricating a compression ignition diesel engine in need of metal wear reduction with a lubricating oil composition comprising (a) a major amount of an oil of lubricating viscosity;

• (b) about 1600 ppm to about 3000 ppm as Ti metal of one or more non-halogen-containing oil-soluble titanium complexes comprising at least one ligand comprising an anion of a carboxylic acid;
• (c) about 0.5 wt. % to about 8 wt. %, based on the total weight of the lubricating oil composition, of one or more dispersants;
• and (d) about 0.2 wt. % to about 8 wt. %, based on the total weight of the lubricating oil composition, of at least two metal-containing detergents including a first metal-containing detergent concentrate which is an overbased alkaline earth metal sulfonate or phenate detergent concentrate or mixture thereof having a BN of about 100 to about 450 and a second metal-containing detergent concentrate which is an overbased alkaline earth metal sulfonate or phenate detergent concentrate or mixture thereof having a BN of about 10 to about 50, wherein the lubricating oil composition is free of any zinc dialkyldithiophosphate, has a sulfated ash content of no more than about 1.0 wt. % as determined by ASTM D874 and is substantially free of any phosphorus content, and further wherein the compression ignition diesel engine is equipped with at least one of an exhaust gas recirculation (EGR) system;
• a catalytic converter;
• and a particulate trap;
• and wherein metal wear reduction occurs even when engine-soot load is maintained.