This repair manual covers engines from the NEF family, including the F4HE, F4CE, F4DE, and F4GE series. These are 6-cylinder, internal combustion diesel engines designed to meet Tier 3 emission standards. While specific model years are not detailed, this documentation provides comprehensive information for maintaining and repairing these robust power units, known for their reliable performance in various applications. This manual serves as an essential resource for owners, mechanics, and technicians. It details all aspects of engine repair, including step-by-step procedures, troubleshooting guidance, and technical specifications. With clear instructions, numbered steps, and helpful illustrations, this English-language manual is designed to facilitate efficient maintenance and repair, ensuring the continued optimal operation of your engine.