This service repair manual provides comprehensive instructions for the maintenance, troubleshooting, and repair of the Mitsubishi 4DQ5 diesel engine. It includes detailed procedures for diagnosing and fixing issues related to the engine’s core components, such as the fuel system, cooling system, lubrication system, and exhaust. The manual offers step-by-step guidance on disassembly, inspection, reassembly, and adjustments, accompanied by technical specifications and detailed diagrams. Additionally, it covers routine maintenance tasks and schedules to ensure the engine operates efficiently and reliably. This document is essential for mechanics and technicians working with the Mitsubishi 4DQ5 diesel engine.