Abstract: A lubricating oil composition and method of lubricating an engine equipped with a diesel particulate filter using the lubricating oil composition. The lubricating oil composition may contain greater than 50 wt. % of a base oil of lubricating viscosity, an amount of one or more calcium-containing detergents to provide less than 1700 ppm calcium, an amount of one or more magnesium-containing detergents to provide less than 450 ppm magnesium, an amount of one or more molybdenum-containing compounds to provide less than 450 ppm molybdenum, from about 700 ppm to about 900 ppm of phosphorus, and a total sulfated ash content of no greater than 1.0 wt. %, all as measured by ASTM D874, based on the total weight of the lubricating oil composition; and a ratio, in ppm, of calcium from the one or more calcium-containing detergents to magnesium from the one or more magnesium-containing detergents of 1:1 or more.