🏷️ Basic Information Identification Make: Mercedes-Benz Model: W123 300D TurboDiesel Model Code: W123 Engine Type: TurboDiesel Engine Designation: OM617 Codes Chassis Code: W123 👋 Introduction Market Position Vehicle Segment: Mid-size Luxury/Executive Sedan and Estate, renowned for durability and engineering. Competitive Analysis Contemporary Competitors: BMW 5 Series (E28), Audi 100, Volvo 240 series, and other European luxury sedans of the era. Key Features Model Reputation: The W123 is widely celebrated for its robust build quality, exceptional longevity, and the reliable OM617 diesel engine, often cited as one of Mercedes-Benz's finest engines. Manual Value Proposition Cost Effectiveness: An inexpensive way to maintain and repair the vehicle, empowering owners to perform tasks themselves and save on dealership service costs. 📋 Manual Details Coverage Areas Covered Years: 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985 Body Styles Covered: Sedan, Coupe, Wagon (Estate/T-Model), potentially others depending on manual's scope Page Count Estimated Page Count: Likely 800+ pages, typical for comprehensive workshop manuals of this era. Manual Type Manual Type: Workshop Service and Repair Manual Language Language: English Format File Format: PDF 📖 Manual Coverage Systems Covered Engine Management: Detailed diagnosis and repair of the OM617 TurboDiesel engine, including fuel injection system, turbocharger, glow plug system, and cooling system. Drivetrain: Coverage of manual and automatic transmissions, clutch, driveshafts, differential, and axles. Suspension Steering: Front and rear suspension components, shock absorbers, springs, control arms, steering gear, power steering system, and wheel alignment procedures. Brakes: Hydraulic brake system, including front and rear disc brakes, brake calipers, master cylinder, brake lines, parking brake, and ABS diagnostics (if equipped on later models). Electrical System: Comprehensive wiring diagrams, battery, charging system (alternator), starting system, lighting system, ignition system, instrument cluster, power windows, and other electrical accessories. Body And Chassis: Body panel repair, door mechanisms, window regulators, interior trim, body sealant, and structural components. Procedures Included Routine Maintenance: Oil changes, filter replacements, fluid checks and top-offs, spark plug replacement (for gasoline variants, but relevant context for a comprehensive manual), air filter replacement, tire rotation and pressure checks. Engine Overhaul: Detailed instructions for engine disassembly, component inspection, repair, and reassembly, including piston ring replacement, valve adjustments, and cylinder head gasket replacement. Transmission Repair: Step-by-step guides for rebuilding or repairing both manual and automatic transmissions. Brake System Repair: Brake pad and rotor replacement, caliper rebuilding, brake fluid flush and bleeding procedures. Electrical Troubleshooting: Diagnostic procedures for electrical faults, using wiring diagrams, and testing electrical components. Diagnostics: Troubleshooting guides for common problems, symptom-based diagnostics, and specific component testing procedures. Technical Depth Repair Scope: Covers everything from basic maintenance to complete engine and transmission rebuilds, including in-depth electrical diagnostics and bodywork. Illustrations Quality: Hundreds of detailed photos, drawings, and exploded views to guide repairs. Includes enlarged inset views for intricate components. Target Audience: Suitable for both DIY enthusiasts and experienced professional mechanics due to its comprehensive detail. 📊 Manual Specifications File Format File Format: PDF Print Quality Printable Pages: Full Printable (allows printing of all pages) Zoom Capability: YES (Zoom IN/OUT functionality in PDF reader) Binding Type Binding Type: Digital Download (no physical binding) Paper Type Paper Type: N/A (Digital Format) Delivery Delivery Method: Instant Download Requirements Software Requirements: Adobe PDF Reader & WinZip Compatibility Operating Systems: Compatible with All Versions of Windows & Mac ⚙️ Engine Specifications Primary Engine Engine Model: OM617.912 (Turbocharged) Engine Configuration: Inline 5-cylinder, Naturally Aspirated version (OM617.912) also common without turbo. Displacement: 3.0 Liters (2998 cc) Performance Horsepower: Approximately 80-90 hp for naturally aspirated, 115-125 hp for turbocharged models (depending on specific market and tuning). Torque: Approximately 130-145 lb-ft for turbocharged models. Fuel System Injection System: Bosch inline injection pump with mechanical injectors. Fuel Type: Diesel 🔧 Transmission Standard Standard Transmission: 4-speed Manual Transmission (often standard on lower trims) Optional Optional Transmission: 4-speed Automatic Transmission (very common) Features Transmission Features: The automatic transmission was known for its robust construction and smooth operation, though later models offered improved versions. 📐 Dimensions Exterior Wheelbase: Approximately 2810 mm (110.6 inches) for sedan, longer for wagon. Length: Varies by body style, sedan around 4750 mm (187 in). Weights Curb Weight: Approximately 1450-1550 kg (3200-3400 lbs) depending on configuration. Gross Vehicle Weight Rating: Typically around 2000-2100 kg (4400-4600 lbs). 🛡️ Safety Features Passive Features Seatbelts: Standard front seatbelts, optional rear seatbelts. Later models may have inertia-reel belts. Crumple Zones: Designed with significant crumple zones for passive safety, a hallmark of Mercedes-Benz engineering. Body Structure: Reinforced passenger cell for enhanced occupant protection. 💡 Technology Features Infotainment Original Infotainment: Basic AM/FM radio, potentially with cassette player. Analog instrumentation for all functions. Driver Assistance Driver Assistance Features: Limited to mechanical systems like power steering. No electronic driver assistance systems (e.g., ABS, traction control) were standard or widely available on early models. Connectivity Connectivity Features: None by modern standards. Features focused on mechanical reliability and comfort. 🔧 Maintenance...