Effective control of lube oil contaminants is rapidly becoming of critical concern to diesel engine manufacturers. The key force creating this concern is engine design changes resulting from more restrictive diesel emissions regulations. As a result of these changes, more contaminants from combustion as well as those from component wear are being retained in the crankcase, severely challenging oil additive and engine durability.In this study, two identical 2.0 liter direct-injection turbocharged diesel engines were repetitively loaded through a 120 minute maximum-torque, maximum-power, maximum-speed cycle, and wear was accelerated by a forced injection of Air Cleaner Fine Test Dust (AC Spark Plug Division, GMC) into the lubrication circuit.The baseline design engine used the standard factory-equipped lube filter while the other was equipped with a block-mounted bypass oil cleaning centrifuge in addition to the standard full-flow filter. Online data-acquisition equipment monitored wear-related performance characteristics. After-test measurements compared total wear and surface profiles on seven engine components over the 150 hour test.Test results showed dramatic reductions in piston ring blow-by and component wear through application of the centrifuge oil cleaner. At test end, blow-by on the uncontrolled baseline engine was 140% higher than on the test engine equipped with the centrifuge. In addition, piston ring weight loss was 90% less than that experienced with the baseline engine filter system. In this report, the engine accelerated wear test results are complemented with a summary of North American field experience from major heavy-duty line-haul truck fleet users of the oil cleaning centrifuge.