This manual pertains to the Isuzu 4HK1-6HK1 Engine, a robust diesel engine family designed for demanding applications. These engines are known for their reliability and engineering quality, featuring common rail direct injection for efficient fuel delivery. The 4HK1 variant offers a 5.2-liter displacement, while the 6HK1 provides a larger 7.8-liter capacity, both engineered with precision bore and stroke dimensions to ensure optimal performance and durability. This comprehensive Service Repair Workshop Manual, available in English, provides essential information for maintaining and repairing the Isuzu 4HK1-6HK1 Engine. It covers a wide range of critical areas including detailed maintenance checklists, troubleshooting guides, servicing specifications, tightening torques, and procedures for disassembling and servicing various components such as the fuel filter and alternator. With clear diagrams, illustrations, and wiring schematics, this manual is an indispensable resource for owners, mechanics, and technicians seeking to ensure the longevity and peak performance of their Isuzu engines.