The Series 60 engine is a heavy duty, four stroke cycle, diesel engine designed for automotive applications primarily in on-highway trucks. In March, 1987, production started making 11.1L (677 in.3) and 12.7L (774 in.3) engines rated from 250-400 HP (187-298 KW). These engines are very fuel efficient due to the incorporation of electronic controls, electronic unit injectors, overhead camshaft and air to air charge air cooling. New, improved electronic controls, DDEC II, have been released for the 1988 models to enhance diagnostics, ease installation and add programming flexibility. DDEC II also is used to control noise during engine acceleration. This, combined with built-in engine design features, assists the truck manufacturer in meeting the 1988 noise standards.Both Federal and California emissions certificates have been received for 1988. Only programming differences are needed for the two types of certification. Fuel economy was improved from 1987 ratings due to air system improvements. Driveability testing and fuel consumption mapping have characterized the performance of the engine. This data is used to optimize the driveline specifications for both fuel economy and driver satisfaction.Heavy duty features were designed throughout the engine in order to assure long life and reliable performance. There is a gear train in the front which drives pumps, accessories and pulleys. A variety of fan locations, intake manifolds, exhaust manifolds, oil pans and air compressors are available which allow flexibility and customer selection. A Jacobs Brake has been designed for this engine.Details of reliability and durability probe tests are presented. The probe test approach finds the weak link by progressively increasing five stress variables simultaneously until a failure or distress is created. Design changes are then made to eliminate the failure modes.