🏷️ Basic Information Identification Make: Mercedes-Benz Model: 300TD Model Code: W123 (specifically relevant to the 300TD variant) Production Years Covered: 1976-1985 Codes Engine Code: OM617 (5-cylinder turbocharged diesel) 👋 Introduction Market Position Segment: Mid-size Luxury Sedan/Wagon Target Audience: Affluent consumers seeking robust, reliable, and comfortable transportation with a focus on diesel efficiency and build quality. Competitive Analysis Key Competitors: BMW 5 Series (E28), Audi 100/200, Volvo 240/260, Cadillac Seville, Lincoln Continental. Key Features Distinctive Attributes: Legendary Mercedes-Benz build quality and durability, the robust and fuel-efficient OM617 turbocharged diesel engine, comfortable and spacious interior, advanced safety features for its time, sophisticated ride quality. Manual Value Proposition: Provides authorized diagnostic and repair procedures directly from the manufacturer, ensuring accuracy and completeness for maintaining these classic vehicles. 📋 Manual Details Coverage Areas Primary Coverage: North America Regional Variants: Likely covers common specifications for US and Canadian market models, with potential for European variations if applicable to the W123 platform. Page Count Estimated Page Count: Approximately 1000-1500+ pages (typical for comprehensive factory service manuals of this era, though exact count not provided). Manual Type Type: Factory Service and Repair Manual / Workshop Manual Language Language: English Format Format: Digital Download (PDF) 📖 Manual Coverage Systems Covered Powertrain: Engine (OM617, 3.0L Turbo Diesel), Fuel System (Injection Pump, Injectors, Glow Plugs), Exhaust System, Cooling System, Lubrication System. Drivetrain: Transmission (Automatic 4-speed, likely 722.1), Clutch (if applicable to manual variants, though 300TD was predominantly automatic), Driveshafts, Differentials. Chassis: Suspension (Front Independent, Rear Independent Swing Axle), Steering System (Recirculating Ball Power Steering), Brakes (Hydraulic, Front Disc, Rear Drum or Disc depending on year/market), Wheels and Tires. Electrical: Battery, Charging System (Alternator), Starting System, Ignition System (Diesel Pre-glow), Lighting System, Gauges and Instruments, Wiper/Washer System, HVAC Controls, Power Accessories (Windows, Locks, Antenna). Body: Body structure, Doors, Hood, Trunk, Bumpers, Glass, Seals, Interior Trim, Seats. Procedures Included Maintenance: Oil Changes, Filter Replacements (Oil, Fuel, Air), Fluid Level Checks and Top-offs, Belt Adjustments and Replacements, Brake Pad/Shoe Replacement, Spark Plug/Glow Plug Checks. Troubleshooting: Diagnostic procedures for common starting issues, engine performance problems, electrical faults, and drivability concerns, likely utilizing symptom-based charts. Repair Overhaul: Detailed step-by-step instructions for component disassembly, repair, reassembly, and adjustment, including engine rebuild, transmission overhaul, suspension component replacement, brake system repair, and electrical component replacement. Specifications Data: Torque specifications for critical fasteners, diagnostic data (e.g., injection timing, valve clearances, compression ratios), fluid capacities, lubrication points, and wiring diagrams. Technical Depth Depth: Comprehensive, covering everything from basic routine maintenance to complete engine and transmission overhauls, advanced electrical diagnostics, and bodywork repairs. Suitable for professional technicians and experienced DIY enthusiasts. 📊 Manual Specifications File Format Format: PDF Searchability: Likely text-searchable, facilitating quick access to specific information. Print Quality Quality: High resolution scans, designed for clear readability of text and diagrams. Binding Type Binding: N/A (Digital Download) Paper Type Paper Type: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Type: Inline 5-Cylinder, Naturally Aspirated (later turbocharged) Engine Code: OM617.912 (for 300TD in this era, turbocharger common) Displacement: 3.0 Liters (2998 cc) Bore X Stroke: 87.0 mm x 100.0 mm Compression Ratio: 21.0:1 (approximate) Performance Horsepower: Approx. 80-85 hp (naturally aspirated), Approx. 110-125 hp (turbocharged, depending on specific market and year). Torque: Approx. 130-140 lb-ft (naturally aspirated), Approx. 170-180 lb-ft (turbocharged, depending on specific market and year). Fuel System Fuel Type: Diesel Injection System: Bosch Mechanical Inline Injection Pump and Injectors Air Intake: Naturally Aspirated or Turbocharged with Intercooler (later models). Cooling System Cooling Type: Liquid Cooled Lubrication Oil Capacity: Approx. 7.5 liters (with filter) 🔧 Transmission Standard Transmission Type: 4-Speed Automatic (Model 722.1) Optional Optional Transmission: 5-Speed Manual (less common on 300TD, more prevalent on 300D sedan). Features Automatic Features: Torque Converter Lock-up (on some later models), Hydraulic Control. Fluid Spec Automatic Transmission Fluid: MB Specification 236.1 (e.g., Dexron II compatible, but always check manual for exact spec). 📐 Dimensions Exterior Body Styles: Sedan (W123), Wagon (S123) Length: Sedan: ~187.0 in (4750 mm), Wagon: ~191.7 in (4870 mm) Width: Approx. 69.5 in (1765 mm) Height: Sedan: ~55.7 in (1415 mm), Wagon: ~56.7 in (1440 mm) Weights Curb Weight: Approx. 3400-3700 lbs (1540-1680 kg), depending on body style and equipment. 🛡️ Safety Features Ratings Historical Ratings: While official NHTSA ratings were not as standardized as today, Mercedes-Benz of this era was known for robust safety engineering and crashworthiness for its time. Active Features Active Safety: Four-wheel disc brakes (on some later models, otherwise front disc/rear drum), Power steering, Anti-lock Braking System (ABS) became available on later W123 models. Passive Features Passive Safety: Reinforced passenger compartment, crumple zones, padded dashboard, safety belts (three-point front, two-point rear initially, evolving to three-point rear), dual-pane safety glass. 💡 Technology Features Infotainment Audio System: Factory AM/FM radio, optional cassette player. Limited integration by modern standards, but functional for its era. Driver Assistance Early Systems: Cruise control...