🏷️ Basic Information Identification Make: Mercedes-Benz Model: 300 CD Year: 1985 Codes Chassis Code: W123 👋 Introduction Market Position Category: Luxury Diesel Sedan/Coupe Segment: Mid-size Luxury Competitive Analysis Key Competitors: BMW 5 Series (E28), Audi 5000 (C2/C3), Cadillac Seville Key Features Powertrain Reliability: Renowned for the durability and longevity of its OM617 diesel engine. Build Quality: Exceptional Mercedes-Benz build quality, typical of the W123 era. Fuel Economy: Excellent fuel efficiency for its class and era, a major selling point for the diesel models. Comfort Ride: Supple ride quality and comfortable interior appointments. Manual Value Proposition Diy Savings: Significant cost savings by empowering owners to perform routine maintenance and repairs. Technical Expertise: Provides factory-level technical understanding for enthusiasts and mechanics alike. 📋 Manual Details Coverage Areas Primary Coverage: Service, Repair, Maintenance, Troubleshooting, Diagnostics Secondary Coverage: Wiring Diagrams, Specifications, Procedures Page Count Estimated Page Count: 1000+ Manual Type Type: Factory Service Manual (WSM) Language Language: English Format Format: Digital Download (PDF) 📖 Manual Coverage Systems Covered Powertrain: Engine (OM617.952), Fuel System (Diesel Injection), Exhaust System, Cooling System, Lubrication System Drivetrain: Transmission (4-Speed Automatic), Driveshafts, Rear Axle, Differential Suspension Steering: Front Suspension (Independent), Rear Suspension (Independent), Steering System (Power Steering) Brakes: Front Disc Brakes, Rear Disc Brakes, Parking Brake, Hydraulic System, ABS (if equipped) Electrical: Battery, Alternator, Starter Motor, Ignition System (Glow Plugs), Lighting System, Instrumentation, Wiring Diagrams Body Chassis: Body Panels, Doors, Windows, Seats, Interior Trim, Chassis Components, Corrosion Protection Procedures Included Maintenance: Oil Change, Filter Replacement (Oil, Fuel, Air), Fluid Checks and Replacements, Tune-Up Procedures, Belt Inspection/Replacement Repair: Engine Overhaul, Transmission Rebuild, Brake System Repair, Suspension Component Replacement, Electrical Component Diagnosis and Repair Troubleshooting: Diagnostic Charts, Symptom-Based Troubleshooting, Component Testing Technical Depth Depth: Comprehensive: From basic fluid changes to complete engine and transmission overhauls, including detailed diagnostic procedures and electrical schematic interpretation. 📊 Manual Specifications File Format Digital Format: PDF Searchability: Text-searchable (OCR optimized) Print Quality Resolution: High-resolution for clear text and diagrams Binding Type Binding: N/A (Digital Download) Paper Type Paper Quality: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Code: OM617.952 Configuration: Inline 5-cylinder Displacement: 3.0 Liters (2998 cc) Aspiration: Naturally Aspirated Diesel Performance Horsepower: 85 hp @ 4200 rpm Torque: 135 lb-ft @ 2400 rpm Fuel System Injection Type: Bosch Inline Fuel Injection Pump (Mechanical) Fuel Type: Diesel Fuel Engine Features Valvetrain: SOHC (Single Overhead Camshaft) Glow Plugs: Yes, essential for cold starts 🔧 Transmission Standard Type: 4-Speed Automatic (722.3) Optional Type: 5-Speed Manual (rare for 300CD) Features Torque Converter: Yes (for automatic) Fluid Specifications Automatic Transmission Fluid: MB Specification 236.1 or 236.2 (e.g., Dexron II compatible) 📐 Dimensions Exterior Body Styles: Coupe (C123), Sedan (W123) Wheelbase: 108.7 inches (2761 mm) Length: 188.2 inches (4780 mm) Width: 69.5 inches (1765 mm) Height: 54.8 inches (1392 mm) Weights Curb Weight: Approx. 3400-3600 lbs (1542-1633 kg) Gross Vehicle Weight Rating: Approx. 4500 lbs (2041 kg) 🛡️ Safety Features Ratings Crash Test Data: Limited official crash test data from modern standards, but known for robust construction. Active Features Brakes: Four-wheel disc brakes (standard on many models/trims), optional ABS (Anti-lock Braking System). Steering: Recirculating ball steering system with power assist. Passive Features Seatbelts: Three-point front seatbelts, lap belts in rear. Construction: Reinforced passenger safety cell, crumple zones. 💡 Technology Features Infotainment Audio System: Factory fitted AM/FM stereo with cassette player. Options for premium sound systems existed. Dashboard: Classic Mercedes-Benz dashboard layout with comprehensive instrumentation and wood trim accents. Driver Assistance Cruise Control: Standard on most models. ABS: Optional Anti-lock Braking System (ABS) available on some later models. 🔧 Maintenance Service Intervals Oil Change: Every 3,000-5,000 miles or 6-12 months, depending on driving conditions. Fuel Filter: Every 10,000-15,000 miles (crucial for diesel longevity). Air Filter: Every 15,000-20,000 miles. Transmission Service: Every 30,000-40,000 miles (fluid and filter change). Fluid Specifications Engine Oil: API CD or CE rated Diesel Engine Oil, 15W-40 or 10W-40 recommended (refer to manual for specific viscosity based on climate). Coolant: Ethylene Glycol based antifreeze/coolant, typically a 50/50 mix with distilled water. Mercedes-Benz specifications should be followed. Brake Fluid: DOT 3 or DOT 4 brake fluid. Known Issues Engine Wear: Potential wear on injection pump, injectors, and oil cooler seals over high mileage. Suspension Components: Worn bushings, ball joints, and tie rod ends are common due to age and mileage. Climate Control: Can be complex; vacuum actuators and compressor issues can arise. Body Rust: Rust can affect wheel wells, rocker panels, and door bottoms, especially in areas with road salt. Electrical Connections: Corrosion in connectors and wiring harnesses can lead to intermittent electrical issues. 📚 Vehicle History Brand Heritage Legacy: Mercedes-Benz reputation for engineering excellence, durability, and luxury stretching back decades. Model Evolution W123 Lineage: The W123 generation (1976-1985) is famed for its build quality and reliability. The 300 CD model specifically was a unique coupe offering in the North...