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. 🏷️ Basic Information Identification Make: Mercedes-Benz Model: 450 SEL Chassis Code: W116 Model Years Covered: 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980 Codes Engine Code Primary: M117 👋 Introduction Market Position Target Segment: Luxury Sedan Era: Early to late 1970s luxury automotive segment Competitive Analysis Competitors Era: BMW E23 7 Series, Jaguar XJ, Cadillac Fleetwood, Lincoln Continental Key Features Vehicle Focus: Luxury, comfort, engineering, advanced features for its time Manual Purpose: Empower owners and technicians to perform expert-level maintenance and repairs, maximize vehicle value 📋 Manual Details Coverage Areas Coverage Scope: Comprehensive workshop service and repair Target Audience: Mechanical technicians, experienced DIY enthusiasts Page Count Estimated Page Count: Extensive (Exact count not specified, but described as complete) Manual Type Type: Workshop Service Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine Systems: Engine disassembly, assembly, tune-ups, lubrication, cooling, fuel, ignition, exhaust Drivetrain Systems: Transmission (engine and transmission disassembly for repair/overhaul) Electrical Systems: Full electrical system diagnosis and repair, ignition system Chassis Systems: Brakes, steering, suspension (implied by workshop coverage) Body Systems: Body repair and maintenance procedures Procedures Included Maintenance Procedures: Routine maintenance, servicing, tune-ups Repair Procedures: Diagnostic and repair procedures for various systems, overhaul of major components Installation Procedures: Removal and installation procedures for components and assemblies Troubleshooting: Diagnostic procedures for common and complex issues Technical Depth Depth: Detailed, emphasizing special aspects of the product, includes proprietary component information 📊 Manual Specifications File Format File Type: PDF Printability: Yes Searchability: Implied by PDF format, likely text-searchable Delivery Delivery Method: Electronic delivery via Email Delivery Speed: Fast Binding Type Binding: N/A (Digital format) Paper Type Paper Type: N/A (Digital format) ⚙️ Engine Specifications Primary Engine Engine Type: V8, Four-stroke internal combustion Engine Displacement Liters: 4.5 Engine Displacement Cubic Inches: 276 Performance Horsepower Approx Net: 220-230 hp (SAE Net, specific to year/market variations) Torque Approx Net Lb Ft: 270-280 lb-ft (SAE Net, specific to year/market variations) Fuel System Fuel Delivery: Bosch K-Jetronic Fuel Injection (for most later models and common variants) Fuel Type: Unleaded Gasoline 🔧 Transmission Standard Type: Automatic Model: Mercedes-Benz 3-speed Automatic (e.g., 4G-Tronic) Optional Availability: Manual transmissions were extremely rare or not offered on the 450 SEL in North America. Features Transmission Cooling: Integrated transmission fluid cooler (typically via radiator) 📐 Dimensions Exterior Wheelbase Inches: 116.7 inches (approx.) Overall Length Inches: 199.9 inches (approx.) Overall Width Inches: 70.5 inches (approx.) Weights Curb Weight Lbs: 3900 - 4200 lbs (approx.) 🛡️ Safety Features Ratings Safety Features Era: Advanced for its time: Crumple zones, safety steering column, reinforced cabin, laminated windshield Active Features Brakes: Power-assisted 4-wheel disc brakes, often with ABS (Anti-lock Braking System) on later models (e.g., 1978 onwards) Passive Features Seatbelts: Front and rear seatbelts 💡 Technology Features Infotainment Audio System: Factory AM/FM radio, often with cassette player as an option. Soundproofing for a quiet cabin was a key feature. Driver Assistance ABS: Anti-lock Braking System (ABS) available on later models, a significant technological advancement for the time. Climate Control HVAC: Advanced (for the era) automatic climate control system with air conditioning and heating. Comfort Features Power Features: Power windows, power locks, power steering, power seats (often with memory function), cruise control. 🔧 Maintenance Service Intervals Oil Change Interval Miles: Every 5,000 - 7,500 miles (or 6-12 months, depending on driving conditions and oil type used, consult manual for specifics) Tune Up Interval: As needed or every 20,000 - 30,000 miles, focus on ignition timing, fuel mixture, and spark plugs. Fluid Specifications Engine Oil Type: API SG or higher, SAE 10W-40 or 15W-40...