🏷️ Basic Information Identification Make: Mercedes-Benz Model: 300SD Chassis Code: W126 Years Covered: 1981-1985 👋 Introduction Market Position Segment: Luxury Sedan Target Audience: Mercedes-Benz owners, independent repair shops, automotive enthusiasts Competitive Analysis Key Competitors: BMW 5 Series (E28), Audi 5000, Cadillac Sedan de Ville, Lincoln Continental Key Features Vehicle Attributes: Renowned for build quality, durability, comfort, and innovative engineering; the OM617 diesel engine is legendary for its longevity and fuel efficiency. Manual Value: Provides professional-level repair and maintenance information, enabling owners to maintain their vehicles to factory standards, increasing longevity and resale value. 📋 Manual Details Coverage Areas Manual Type: Factory Service Repair Workshop Manual Language: English Format: PDF Download Digital Rights: Unlimited use, no expiry Device Compatibility: Windows, MAC, Tablets, Smartphones 📖 Manual Coverage Systems Covered Engine Mechanical: OM617.951 diesel engine, disassembly, assembly, overhaul, timing, lubrication, cooling Engine Management: Fuel injection system (Bosch inline injection pump), glow plug system, engine control unit (if applicable) Transmission: 4-speed automatic transmission (722.3), service, repair, adjustments, fluid specifications Drivetrain: Driveshaft, rear axle, differential, wheel bearings Suspension: Front and rear suspension components, springs, shock absorbers, control arms, bushings, alignment specifications Steering: Power steering system, steering box, tie rods, steering linkage, maintenance and repair Brakes: Front and rear disc brakes, brake calipers, master cylinder, brake lines, parking brake, ABS (Anti-lock Braking System) components and troubleshooting Electrical System: Battery, charging system (alternator), starter motor, ignition system (pre-glow), lighting, fuses, relays, wiring diagrams Climate Control: Air conditioning system, heater core, blower motor, controls, refrigerant service (caution advised) Body And Chassis: Body panels, doors, hood, trunk, interior trim, structural components, rust prevention Body Electrical: Power windows, power door locks, central locking, power seats, mirrors, wipers, horn Procedures Included Routine Maintenance: Oil changes, filter replacements, fluid checks and top-offs, lubrication points, tire rotation Troubleshooting: Diagnostic procedures, symptom-based troubleshooting, fault code interpretation (if applicable) Repair Procedures: Step-by-step instructions for all major mechanical and electrical components Overhaul Procedures: Detailed rebuild procedures for engine, transmission, and other major systems Installation Procedures: Guidance on installing new or replacement parts Technical Specifications: Torque values, clearances, fluid capacities, electrical specifications, diagnostic data Technical Depth Depth Of Coverage: Comprehensive: Covers all aspects from basic maintenance to full engine and transmission rebuilds, including detailed diagnostics and schematics. 📊 Manual Specifications File Format File Format: PDF Searchable: Yes, text-searchable PDF Printability: Printable (individual pages or entire manual) Image Quality: High-resolution photos and diagrams Binding Type Binding Type: Digital Download (not a physical book) Paper Type Paper Type: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Engine Code: OM617.951 Engine Type: Inline 5-cylinder Diesel Displacement: 2998 cc (3.0 Liters) Performance Horsepower: 123 hp @ 4350 rpm (approx.) Torque: 184 lb-ft @ 2400 rpm (approx.) Fuel System Injection System: Bosch Inline Injection Pump with Mechanical Governor Fuel Type: Diesel Fuel (refer to manual for specific grade recommendations) Cooling System Cooling Type: Liquid-Cooled, Thermostatically Controlled Lubrication Oil Capacity: 7.5 Liters (approx.) with filter change 🔧 Transmission Standard Type: 4-Speed Automatic (722.3) Optional Type: Not applicable for 300SD in this range Features Transmission Fluid: MB 236.1 Specification Automatic Transmission Fluid (ATF) Transmission Fluid Capacity: Approximately 7.0-7.5 Liters (refer to manual for exact capacity) 📐 Dimensions Exterior Length: 4995 mm (196.7 in) Width: 1798 mm (70.8 in) Height: 1440 mm (56.7 in) Weights Curb Weight: Approx. 1750 kg (3858 lbs) Gross Vehicle Weight Rating: Approx. 2300 kg (5070 lbs) 🛡️ Safety Features Ratings Crash Test Data: NHTSA ratings for this era are less standardized. Emphasis on robust chassis construction and passive safety features. Active Features ABS: Available on later models within this range (e.g., 1984-1985) Passive Features Airbags: Driver airbag became standard on later W126 models (typically from 1984/1985 onwards). Seatbelts: 3-point front and rear seatbelts, seatbelt pre-tensioners (depending on year/market). Chassis Design: Advanced crumple zones, reinforced safety cage. 💡 Technology Features Infotainment Audio System: Factory installed radio and cassette player (Becker brand often fitted). Manual covers basic operation and troubleshooting. Driver Assistance Cruise Control: Standard feature, covers operation and basic maintenance. Connectivity Tele Aid: Not available for this era. 🔧 Maintenance Service Intervals Oil Change Interval: Every 5,000-7,500 miles or 6-12 months (refer to manual for specific conditions and oil type). Air Filter Replacement: Every 15,000-20,000 miles or as needed based on operating conditions. Fuel Filter Replacement: Every 15,000-25,000 miles (crucial for diesel engine health). Transmission Fluid Change: Every 30,000-50,000 miles or as recommended by the manual. Critical for longevity of the 722.3 transmission. Fluid Specifications Engine Oil Spec: API CD or CE rated diesel engine oil, viscosity grade 15W-40 or 20W-50 depending on ambient temperature (refer to manual). Coolant Spec: Mercedes-Benz approved coolant (e.g., silicate-free, ethylene glycol-based) in a 50/50 mixture with distilled water. Brake Fluid Spec: DOT 3 or DOT 4 brake fluid (ensure compatibility as per manual). Known Issues Engine Mounts: Wear and tear leading to vibration transmitted to...