🏷️ Basic Information Identification Make: Mercedes-Benz Model: 300 CD Year: 1981 Codes Chassis Code: W123 Engine Code: OM617 👋 Introduction Market Position Market Segment: Luxury Mid-Size Diesel Sedan/Coupe Competitive Analysis Key Competitors: BMW 5 Series Diesel, Audi 5000 Diesel (though less prevalent in North America), Volvo Diesel variants. Key Features Brand Perception: Reputation for build quality, durability, and sophisticated engineering. Powertrain Emphasis: Renowned for its robust and fuel-efficient OM617 turbocharged diesel engine. Manual Value Proposition Value To Owner: Enables owners to perform dealer-level maintenance and repairs, saving costs and ensuring longevity. 📋 Manual Details Coverage Areas Primary Coverage: Service, Repair, Maintenance Secondary Coverage: Diagnostics, Troubleshooting, Adjustments, Inspections Page Count Estimated Page Count: Varies by exact manual, but factory manuals are typically extensive, often exceeding 1000 pages for a full set. Manual Type Type: Factory Service Manual / Workshop Manual Language Language: English Format Format: Digital Download (PDF) 📖 Manual Coverage Systems Covered Engine: OM617 Diesel Engine (including fuel injection, cooling, lubrication, exhaust) Transmission: Manual and Automatic Transmissions (fluid changes, level checks, adjustments) Suspension: Front and Rear Axles, Suspension Components, Level Control (ADS), Self-Leveling Suspension Brakes: Hydraulic Brake System (fluid, lines, pads, discs, parking brake), ABS (if equipped) Steering: Power Steering System (fluid, play, adjustments) Electrical: Starting and Charging System, Lighting, Warning Lamps, Sensors, Fuses, Relays Bodywork: Body Structure Inspection, Water Leakage, Corrosion, Door Hinges, Hood, Sunroof, Soft Top, Wiper/Washer System, Doors, Locks, Windshield HVAC: Heating and Ventilation System, Coolant, AC Refrigerant Charge, Filters (Dust, Charcoal, Recirculating Air) Procedures Included Maintenance: Regular Scheduled Maintenance, Oil and Filter Changes, Fluid Replenishments, Belt Tensioning, Filter Replacements, Lubrication Engine Repair: Valve Clearance Adjustment, Injection Timing Adjustment, Fuel Filter Replacement, Spark Plug Replacement (if applicable to diesel variant), Manifold Seating Checks Transmission Repair: Fluid and Filter Changes, Oil Level Checks and Corrections for Manual and Automatic Transmissions, Clutch System Checks Suspension Steering Repair: Ball Joint Inspection, Axle Oil Level Checks, Steering Play Adjustment, Wheel Bolt Tightening, Drive Shaft Coupling Inspection Brake Repair: Brake Fluid Replacement, Parking Brake Adjustment, Brake Pad and Disc Inspection, Brake Line Inspection Electrical Diagnostics: Warning Lamp Checks, Battery Fluid Level Checks, Headlamp and Exterior Lamp Inspection Body And Trim: Lower Panel Removal/Installation, Lubrication of Hinges and Locks, Sunroof Rail Cleaning, Soft Top Inspection Technical Depth Depth: Comprehensive, covering all aspects from routine maintenance to component overhaul and diagnostic procedures. Diagnostic Procedures: Includes guidance for troubleshooting common issues and diagnostic checks for various systems. Specifications: Provides detailed technical specifications, tolerances, and torque values. 📊 Manual Specifications File Format Format: PDF Searchability: Fully searchable text Print Quality Printability: All pages printable Binding Type Binding: N/A (Digital Download) Paper Type Paper Type: N/A (Digital Download) Authenticity Source: Factory Original (stated as 'real files not scans') ⚙️ Engine Specifications Primary Engine Engine Type: Inline 5-cylinder Diesel Displacement: 3.0 Liters (2999 cc) Aspiration: Naturally Aspirated (for the 300 CD designation, though a turbocharged version, OM617.95x, was common in the US market for similar models like the 300D and 300TD) Performance Horsepower: Approximately 77-83 hp (for naturally aspirated variants, turbocharged versions produced more) Torque: Approximately 134-145 lb-ft (for naturally aspirated variants, turbocharged versions produced more) Fuel System Injection System: Bosch Inline Fuel Injection Pump with Mechanical Governor Fuel Type: Diesel Fuel Cooling System Coolant Type: Ethylene Glycol based antifreeze/coolant (Mercedes-Benz recommends specific types, consult manual for part numbers like MB 325.0 or equivalent) Lubrication System Oil Type: API CD or CE rated diesel engine oil. Viscosity typically SAE 15W-40 or 10W-40 depending on climate. Consult manual for specific MB specifications. Oil Capacity: Approximately 7.5 liters (8 US quarts) with filter change. Air Intake Air Filter Type: Paper element filter, potentially a metal-reinforced cleaning type. 🔧 Transmission Standard Type: 4-Speed Manual Transmission (common) Optional Type: 4-Speed Automatic Transmission (common) Features Manual Fluid Type: Manual Transmission Fluid (MTF), typically GL-4 rated. Consult manual for specific MB specification (e.g., MB 235.0). Automatic Fluid Type: Dexron II or equivalent ATF. Consult manual for specific MB specification (e.g., MB 236.6). Clutch Type: Hydraulically actuated single dry plate clutch for manual transmission. 📐 Dimensions Exterior Body Styles: Coupe (C123) Weights Curb Weight: Approximately 1450-1550 kg (3197-3417 lbs) depending on equipment. 🛡️ Safety Features Ratings Crash Testing: NHTSA ratings for this era are generally not comparable to modern standards. Emphasis was on structural integrity and passive safety features. Active Features Brake Assist: Not present in the modern sense; emphasis on robust hydraulic braking. Passive Features Airbags: Not standard on this model year. Seatbelts: Standard front seatbelts, with options for rear seatbelts. Three-point inertial reel belts were becoming more common. Structure: Reinforced body structure, crumple zones designed for the era. 💡 Technology Features Infotainment Audio System: Typically an AM/FM radio with cassette player. Some may have upgraded aftermarket systems. Driver Assistance ABS: Optional on some W123 models, but not universally standard. If equipped, the manual...