This service repair manual covers the Isuzu 4HK1-6HK1 engine, specifically for use in the New Holland E385 (Tier 3) equipment. Engineered by Isuzu, these engines are recognized for their robust performance and reliability, making them a critical component for demanding operational environments. This manual provides comprehensive information to ensure the optimal functioning and longevity of your engine. The purpose of this 335-page English-language manual is to serve as an authoritative guide for maintenance, servicing, and repair. It includes detailed repair procedures, technical maintenance guidelines, troubleshooting steps, and diagnostic information, supported by wiring diagrams, hydraulic diagrams, photo illustrations, and schemes. This resource is designed to assist owners, mechanics, and technicians in effectively maintaining and repairing the specified engine models, ensuring peak operational efficiency and safety.