In our earlier work , an investigation was conducted to study lubricant formulation effects, engine type and mode of engine operation on the composition and nature of diesel soot and its interactions with the crankcase lubricant. Tests were run in two types of heavy duty diesel engines the Mack EM6-285 and the GM 6.2L. Part 2 studies the impact of oil composition on the surface and bulk chemistry of soot and on the ability of the fluid to handle soot produced in the GM 6.5L engine. The study also determined what portion of lubricant viscosity growth is related to bulk oil oxidation versus soot contamination. A statistically designed experiment was developed to examine the effects of dispersant level dispersant type, antioxidant level, and detergent metal type on average roller follower shaft wear, viscosity growth and other measured responses. The effect of run order on these measurements is also studied. Key results of this study are as follows.