🏷️ Basic Information Identification Make: Mercedes-Benz Model: W123 300D Model Generation: First Generation W123 Product Type: Workshop Service Repair Manual Download 👋 Introduction Market Position Vehicle Segment: Mid-size luxury sedan/wagon Brand Reputation: Known for build quality, durability, and engineering excellence Competitive Analysis Key Competitors: BMW 5 Series, Audi 100, Volvo 240 series Key Features Vehicle Focus: Durability, comfort, robust diesel powertrain Manual Benefit: Empowers owners and technicians with factory-level knowledge for effective maintenance and repair 📋 Manual Details Coverage Areas Model Years Covered: 1976-1985 Engine Variants Covered: 3.0L OM617 Diesel Engine Body Styles Covered: All Styles Covered (Sedan, Wagon, Coupe, etc.) Page Count Estimated Page Count: Hundreds of pages (printable) Manual Type Manual Type: Complete Official Full Factory Service Repair Manual Language Language: English Format File Format: PDF Delivery Delivery Method: Instant Download 📖 Manual Coverage Systems Covered Engine: Detailed overhaul, troubleshooting, fuel system, lubrication, cooling, exhaust Transmission: Manual and Automatic Transmission service, overhaul, and troubleshooting Drivetrain: Axles, driveshafts, differential, clutch (if applicable) Brakes: Hydraulic system, calipers, master cylinder, parking brake, troubleshooting Suspension: Front and rear suspension components, alignment specifications, shocks, springs Steering: Power steering system, steering gearbox, linkages, troubleshooting Electrical: Ignition system, charging system (alternator), starting system (starter), lighting, instruments, wiring diagrams Body And Chassis: Body panels, doors, windows, interior trim, chassis components, rust repair guidance HVAC: Heating, ventilation, and air conditioning system maintenance and repair Procedures Included Maintenance: Scheduled maintenance, fluid changes, filter replacements, inspections Repair: Step-by-step repair instructions for all major components and systems Disassembly: Complete disassembly procedures for components and systems Assembly: Detailed assembly procedures with torque specifications Troubleshooting: Diagnostic procedures for common and uncommon issues Cleaning: Component cleaning procedures Reinstallation: Correct reinstallation procedures for all components Technical Depth Depth Of Coverage: Comprehensive: From basic maintenance to complete engine rebuilds and advanced diagnostics Target Audience: Professional technicians and experienced DIY mechanics 📊 Manual Specifications File Format File Format Details: PDF Print Quality Print Quality Description: Full Printable, allows printing of entire manual or select pages Zoom Functionality Zoom Capability: YES (Zoom IN/OUT) Software Requirements Required Software: Adobe PDF Reader, WinZip Compatibility Operating Systems: All Versions of Windows & Mac ⚙️ Engine Specifications Primary Engine Engine Code: OM617 Engine Type: Inline-5 Cylinder, Naturally Aspirated Diesel Displacement: 3.0 Liters (2998 cc) Performance Horsepower: Approx. 72-80 hp (depending on variant and emissions regulations) Torque: Approx. 123-134 lb-ft (167-182 Nm) Fuel System Fuel Injection: Bosch Mechanical Direct Injection Fuel Type: Diesel Cooling System Cooling Type: Liquid-cooled Lubrication Oil Type Specification: API CD or ACEA B3/B4 Specification Diesel Engine Oil (e.g., 15W-40 or 10W-40, consult manual for exact specs) Engine Features Glow Plugs: Essential for cold starting Valve Train: Overhead camshaft (OHC) 🔧 Transmission Standard Transmission Type Standard: 4-speed Manual (early models) or 4-speed Automatic (common) Optional Transmission Type Optional: 5-speed Manual (later models) Features Automatic Transmission: Mercedes-Benz 4G-Tronic (K4B040) – robust and smooth Fluid Specification Automatic Transmission Fluid: MB-Approval 236.1 or 236.2 (e.g., Dexron-II) Manual Transmission Fluid: GL-4 Gear Oil (e.g., 75W-90 or 80W-90) 📐 Dimensions Exterior Wheelbase: Approx. 112.2 inches (2850 mm) Length: Approx. 186.8 - 195.7 inches (4745 - 4970 mm) depending on body style Weights Curb Weight: Approx. 3200 - 3500 lbs (1450 - 1590 kg) depending on body style 🛡️ Safety Features Ratings Crash Safety Philosophy: Designed with a strong emphasis on passive safety and occupant protection for its era. Passive Features Body Structure: Reinforced passenger safety cell, crumple zones Interior: Safety padded dashboard, energy-absorbing steering column Glass: Laminated safety glass for windshield 💡 Technology Features Infotainment Infotainment Features: Basic analog radio (often Becker), analog climate controls. Driver Assistance Driver Assistance Features: Power steering, power brakes (often with ABS on later models). 🔧 Maintenance Service Intervals Oil And Filter Change: Typically every 3,000-5,000 miles (5,000-8,000 km) or annually, refer to manual for exact interval based on usage. Fuel Filter Replacement: Recommended every 15,000-30,000 miles (24,000-48,000 km), critical for diesel health. Air Filter Replacement: Typically every 15,000 miles (24,000 km) or as needed based on operating conditions. Coolant Service: Flush and replace coolant every 2-3 years or per manual recommendation. Fluid Specifications Engine Coolant: MB-Approval 325.0 or 325.2 (Ethylene Glycol based, typically a 50/50 mix with distilled water) Brake Fluid: DOT 3 or DOT 4, high-quality glycol-based brake fluid. Power Steering Fluid: MB-Approval 236.3 (ATF, but specific properties required, consult manual) Known Issues Diesel Specific Issues: Glow plug system reliability, injector pump maintenance, potential for oil leaks from seals and gaskets. Common Wear Items: Suspension bushings, ball joints, exhaust system components, HVAC blower motor. Body Corrosion: Prone to rust in common areas like wheel arches, rocker panels, and around windows; rust prevention is key. Technical Tip Diesel Maintenance Importance: Proper fuel filtration and maintaining the injection system is paramount for the longevity of the OM617 engine. 📚 Vehicle History Brand Heritage Manufacturer: Mercedes-Benz, renowned for engineering and...