This service manual covers the David Brown AD4-25 and CAD4-30 Diesel Engines. These engines are designed for robust performance and reliability, suitable for a variety of demanding applications. Their engineering reflects a commitment to durability and efficient operation, making them a dependable choice for industrial and agricultural use. This manual provides comprehensive guidance for the maintenance and repair of your David Brown diesel engine. It includes detailed procedures, technical specifications, and troubleshooting information essential for ensuring optimal performance and longevity. By following the instructions within this guide, owners and technicians can effectively service and maintain these engines, addressing potential issues and performing necessary upkeep with confidence.