🏷️ Basic Information Identification Make: Mercedes-Benz Model: 300D Chassis Code: W123 Model Years Covered: 1976-1985 Codes Engine Code: OM617 (3.0L Inline-5 Diesel) 👋 Introduction Market Position Vehicle Segment: Mid-size luxury sedan/coupe/wagon, known for durability and comfort. Target Audience For Manual: Mercedes-Benz W123 owners, DIY mechanics, professional automotive technicians, classic car enthusiasts. Competitive Analysis Competitors Vehicle: BMW E21/E30 3 Series, Audi 5000, Volvo 240, Cadillac Seville. Manual Value Proposition: Provides professional-level repair information to maintain and restore a robust and iconic Mercedes-Benz model. Key Features Manual Highlights: Comprehensive coverage, detailed diagrams, step-by-step instructions, professional mechanic-grade content, lifetime access. Vehicle Highlights: Legendary Mercedes-Benz build quality, reliability, durability, comfortable ride, efficient diesel engine. 📋 Manual Details Coverage Areas Manual Type: Full Service & Repair Workshop Manual Language: English (assumed, typical for this market) Format: PDF Download Page Count Page Count Estimate: Hundreds (Specific count not provided, but characteristic of full factory manuals) 📖 Manual Coverage Systems Covered Engine Mechanical: Complete overhaul, disassembly, assembly, timing, valve adjustment, fuel injection system, cooling system, lubrication system. Engine Electrical: Ignition system (if applicable for diesel glow plugs), starting system, charging system, sensors, wiring diagrams. Fuel System: Diesel injection pump, injectors, fuel lines, fuel filters, pre-heating system. Transmission: Manual and automatic transmission overhaul, clutch replacement, shift linkage adjustments, fluid specifications. Drivetrain: Driveshafts, axles, differential, universal joints, lubrication. Suspension: Front and rear suspension components, shock absorbers, springs, bushings, wheel alignment procedures. Steering: Power steering system, steering box, tie rods, steering column, adjustments. Brakes: Hydraulic system, brake fluid, master cylinder, wheel cylinders, brake calipers, brake pads, brake discs, parking brake, bleeding procedures. Electrical System: Battery, starter, alternator, lighting systems, wipers, horn, instrumentation, fuses, relays, wiring diagrams for all circuits. Body And Chassis: Body panel repair, door mechanisms, window regulators, sunroof, interior trim, underbody protection. Heating And Air Conditioning: HVAC system components, refrigerant, blower motor, climate control operation (if equipped). Procedures Included Maintenance: Scheduled maintenance, oil changes, filter replacements, fluid checks and top-offs, lubrication points, belt adjustments. Troubleshooting: Diagnostic procedures for common and uncommon issues, symptom-based troubleshooting guides. Repair: Step-by-step instructions for all major and minor repairs, including complete component rebuilds. Installation: Procedures for replacing or installing new or reconditioned parts. Diagnostics: Detailed diagnostic charts and procedures, often including fault codes if applicable. Technical Depth Depth Of Coverage: Professional-grade, comprehensive, covering all aspects from routine maintenance to complete engine and transmission rebuilds. Diagrams And Illustrations: Hundreds of detailed photos, exploded diagrams, and schematics to illustrate procedures. Torques And Specifications: Precise torque values for all fasteners, critical clearances, and adjustment specifications. 📊 Manual Specifications File Format Digital Format: PDF Compatibility: Windows and MAC OS compatible Access: Instant download, unlimited device usage, lifetime access Print Quality Print Capability: Printable (single page or entire manual) Binding Type Binding Type Digital: N/A (Digital) Paper Type Paper Type Digital: N/A (Digital) ⚙️ Engine Specifications Primary Engine Engine Type: Diesel Engine Configuration: Inline-5 Cylinder Displacement: 3.0 Liters (2998 cc) Bore X Stroke: 87.0 mm x 100.0 mm (typical for OM617) Compression Ratio: 21.0:1 (typical for OM617) Performance Horsepower Est: 77-88 hp @ 4000-4200 rpm (varies slightly by specific OM617 variant) Torque Est: 130-140 lb-ft @ 2400 rpm (varies slightly by specific OM617 variant) Fuel System Fuel Type: Diesel Fuel Injection System: Bosch Mechanical Fuel Injection (Inline Injection Pump) Glow Plug System: Yes, for cold starting assistance. Engine Management Engine Control: Primarily mechanical with some electrical actuation for glow plugs and shutdown. 🔧 Transmission Standard Transmission Type Standard: 4-speed Manual Transmission (e.g., Getrag) Optional Transmission Type Optional: 4-speed Automatic Transmission (e.g., ZF 4HP22) Features Transmission Fluid Spec: Refer to manual for specific ATF type (e.g., Dexron II for automatic). Clutch Type: Single Dry Plate (for manual transmission) 📐 Dimensions Exterior Wheelbase: Approx. 2795 mm (110 inches) Length: Approx. 4730-4770 mm (186.2-187.8 inches) Width: Approx. 1790 mm (70.5 inches) Height: Approx. 1420-1440 mm (55.9-56.7 inches) Weights Curb Weight Est: Approx. 1450-1550 kg (3200-3400 lbs) Gross Vehicle Weight Rating Est: Approx. 2000 kg (4400 lbs) 🛡️ Safety Features Ratings Safety Certification Era: Pre-modern era safety standards; focused on passive safety and build integrity. Active Features Braking System: Four-wheel disc brakes (standard on many later models and optional earlier), ABS not standard on early models, may be present on late W123s. Steering System: Recirculating ball steering with power assist. Passive Features Body Construction: Reinforced safety cage, crumple zones, impact-absorbing steering column, door impact bars. Airbags: Not available for this model range. Seat Belts: Standard front seat belts, optional rear seat belts depending on market and year. 💡 Technology Features Infotainment Infotainment System: Basic analog radio (AM/FM), cassette player (optional). Focus is on mechanical engineering, not electronic entertainment. Driver Assistance Driver Assistance Features: Limited; primarily power steering, optional cruise control, and potentially ABS on later models. Connectivity Connectivity Features: None. 🔧 Maintenance Service Intervals Oil Change Interval Est: Typically every 5,000 -...