This workshop service manual covers the Lombardini 3/4 LD series of diesel internal combustion engines, including models 3LD 450, 3LD 510, 3LD 450/S, 3LD 510/S, 4LD 640, 4LD 705, and 4LD 820. Designed for robust performance in demanding Industrial, Agricultural, and Marine applications, these engines are engineered for reliability and efficiency. This manual provides comprehensive documentation to ensure the optimal operation and longevity of your Lombardini engine.

The purpose of this English-language manual is to serve as an authoritative resource for maintenance, repair, and technical information. It details essential procedures for servicing, troubleshooting, and understanding the technical specifications of the Lombardini 3/4 LD series engines. Owners, mechanics, and technicians will find the detailed instructions and guidelines invaluable for performing routine maintenance, diagnosing issues, and executing repairs, thereby ensuring the continued dependable performance of the equipment.