This manual covers the David Brown Diesel Engine AD4-25, a robust and reliable engine designed for demanding applications. Engineered with precision and built for durability, the AD4-25 represents a commitment to quality and performance. Its design prioritizes efficiency and longevity, making it a trusted choice for various industrial and agricultural needs. The purpose of this Factory Service Repair Manual is to provide comprehensive guidance for the maintenance, repair, and servicing of the David Brown Diesel Engine AD4-25. It details all necessary procedures, technical specifications, and troubleshooting steps to ensure the engine operates at its optimal performance level. This resource is invaluable for owners, technicians, and mechanics seeking to maintain the integrity and functionality of their AD4-25 engine.