This manual covers the Mercedes-Benz W123 300D, produced from 1976 to 1985. As a mid-size luxury sedan and wagon, the W123 is renowned for its exceptional build quality, durability, and the legendary longevity of its inline 5-cylinder diesel engine. It was designed for discerning drivers who valued comfort, safety, and engineering excellence, competing with vehicles like the BMW 5 Series and Audi 100. Key features include a robust chassis, a comfortable ride, and a strong emphasis on passive safety, including pioneering crumple zones.

This comprehensive workshop service repair manual provides detailed information for maintaining and repairing the Mercedes-Benz W123 300D. It covers all essential systems, including the OM617 diesel engine, transmissions, brakes, suspension, steering, and electrical systems. The manual includes step-by-step procedures for routine maintenance, complex diagnostics, and complete overhauls, along with critical technical specifications, special tool requirements, and torque values. This resource is invaluable for owners, mechanics, and technicians seeking to preserve the performance and reliability of their W123 vehicle.