The 450 SEL, chassis code W116, represents a pinnacle of luxury and engineering from the 1973 through 1980 model years. As the first vehicle to bear the S-Class designation, it set a new standard for luxury sedans, rivaling contemporaries like the BMW E23 7 Series and Jaguar XJ. This model is renowned for its exceptional comfort, robust construction, and advanced features for its era, including a powerful 4.5-liter V8 engine (M117) producing approximately 220-230 horsepower, coupled with a 3-speed automatic transmission. Its design emphasized safety, incorporating features like crumple zones and optional Anti-lock Braking System (ABS) on later models, reflecting a commitment to driver and passenger well-being. This comprehensive workshop service and repair manual is designed for mechanical technicians and experienced DIY enthusiasts seeking to maintain and repair their 450 SEL. It covers a vast range of systems, including detailed procedures for engine disassembly, assembly, tune-ups, cooling, fuel, and ignition systems, as well as transmission overhaul and electrical system diagnosis. The manual also addresses chassis and body maintenance, offering routine service guidance and in-depth troubleshooting for common issues such as fuel injection components and aging electrical connections. With its detailed explanations and component information, this manual serves as an essential resource for preserving the longevity and performance of your vehicle.