🏷️ Basic Information Identification Make: Mercedes-Benz Model: 350SD Chassis Code: W126 Model Year: 1991 Codes Engine Code: OM603.960 👋 Introduction Market Position Target Audience: Mercedes-Benz owners (DIY enthusiasts), independent repair shops, Mercedes-Benz technicians Competitive Analysis Advantage: Provides factory-level accuracy and detail, unlike generic aftermarket manuals. Key Features Authenticity: Directly mirrors the documentation used by authorized Mercedes-Benz service centers. Comprehensiveness: Covers all aspects of vehicle service and repair, ensuring no critical information is omitted. 📋 Manual Details Coverage Areas Primary Coverage: Service and Repair Engine Systems: Diesel Engine (OM603.960), Fuel System, Lubrication System, Cooling System, Air Intake and Exhaust, Emission Control Drivetrain Systems: Automatic Transmission (722.5), Drive Shaft, Differential Chassis Systems: Suspension (Front & Rear), Steering System, Brakes (Hydraulic System, ABS) Electrical Systems: Engine Management, Lighting, Instrumentation, Power Accessories, Climate Control, Battery, Charging System Body And Interior: Body Panels, Doors, Windows, Seats, Upholstery, Trim, HVAC Ducts Page Count Estimated Page Count: Over 1500 (estimated for comprehensive factory manual) Manual Type Type: Factory Workshop Service Repair Manual Language Language: English Format Format: HTML/Flash Menu with PDF content Compatibility: Windows (95/98/ME/XP/Vista/7), Linux, macOS 📖 Manual Coverage Systems Covered All Major Systems: Yes Procedures Included Maintenance: Scheduled maintenance, fluid changes, filter replacements, inspections Diagnostics: Troubleshooting charts, fault code interpretation, diagnostic procedures Repair Procedures: Engine component removal/installation/rebuild, transmission overhaul, brake system repair, suspension component replacement, electrical component repair Adjustments: Valve adjustments, timing adjustments, idle speed settings Installation: Accessory installation, component replacement guidelines Technical Depth Depth: Comprehensive - from basic maintenance to complete engine and transmission rebuilds Diagnostic Tools: Includes procedures for using specialized diagnostic tools and equipment common at Mercedes-Benz dealerships. 📊 Manual Specifications File Format Media Type: Digital Download Print Quality Image Resolution: High (typical for factory PDFs) Binding Type Binding: N/A (Digital Format) Paper Type Paper Type: N/A (Digital Format) Searchability Text Search: Searchable PDF content Interactivity Navigation: Interactive HTML/Flash menu for easy navigation ⚙️ Engine Specifications Primary Engine Engine Type: Inline 6-Cylinder Turbocharged Diesel Displacement: 3.5 Liters (3449 cc) Bore X Stroke: 87.0 mm x 92.4 mm Compression Ratio: 22.0:1 Performance Horsepower Net: 134 hp @ 4600 rpm Torque Net: 217 lb-ft @ 2400 rpm Fuel System Injection System: Bosch Inline Injection Pump (VE type) Fuel Type: Diesel Fuel Lubrication System Oil Capacity With Filter: 7.5 Liters (8.0 US Quarts) Recommended Oil Viscosity: SAE 15W-40 Diesel Engine Oil (API CD or higher) Cooling System Coolant Capacity: 11.0 Liters (11.6 US Quarts) Coolant Type: Mercedes-Benz Specification 325.0 (Antifreeze/Coolant, Blue) Emission Control Emission Standards: Federal Tier 1 (USA) / Euro 1 (Europe) 🔧 Transmission Standard Type: 4-Speed Automatic (722.5) Gear Ratios: 1st: 3.68, 2nd: 2.40, 3rd: 1.44, 4th: 1.00, Reverse: 4.20 Transmission Fluid Capacity: 8.0 Liters (8.5 US Quarts) (dry fill) Transmission Fluid Type: MB Spec 236.1 (Dexron II compatible) Features Overdrive: Yes (4th Gear) Lock-Up Torque Converter: Yes 📐 Dimensions Exterior Length: 4960 mm (195.3 in) Width: 1798 mm (70.8 in) Height: 1450 mm (57.1 in) Wheelbase: 2936 mm (115.6 in) Weights Curb Weight: 1780 kg (3924 lbs) Gross Vehicle Weight Rating: 2250 kg (4960 lbs) 🛡️ Safety Features Ratings NHTSA Rating 1991: Driver Side: 4 Stars, Passenger Side: 4 Stars (for sedans of the era) Active Features ABS: Standard (Anti-lock Braking System) Passive Features Airbags: Driver's Side Airbag (Standard) Seatbelts: Front Inertia Reel Seatbelts, Rear Three-Point Seatbelts Crumple Zones: Advanced crumple zones designed for occupant protection. 💡 Technology Features Infotainment Audio System: Factory AM/FM Stereo Cassette Player with optional CD Changer. Driver Assistance Cruise Control: Standard ABS: Standard Anti-lock Braking System Connectivity Post 1990 Features: Early forms of electronic climate control and centralized locking systems operated via vacuum. 🔧 Maintenance Service Intervals Oil Change Interval: Every 10,000 km (6,000 miles) or 12 months, whichever comes first. Air Filter Replacement: Every 40,000 km (24,000 miles) Fuel Filter Replacement: Every 40,000 km (24,000 miles) Transmission Fluid Change: Every 60,000 km (36,000 miles) Coolant Flush: Every 60,000 km (36,000 miles) or 3-4 years Fluid Specifications Power Steering Fluid: MB Spec 236.3 (Dexron II compatible) Brake Fluid: DOT 3 or DOT 4 Hydraulic Brake Fluid Known Issues Diesel Specific: Glow plug issues, injector pump timing, exhaust manifold cracks (common on older diesels), EGR system maintenance. Common W126: Headliner sagging, window regulator failures, vacuum line leaks (affecting central locking, climate control, door locks), SRS system warnings, climate control blower motor resistor failures, ABS sensor issues. Part Numbers Oil Filter Example: Mann Filter W102/2, Bosch 3323 (verify specific application) Air Filter Example: Mann Filter C32170 (verify specific application) 📚 Vehicle History Brand Heritage Mercedes Benz Legacy: Renowned for engineering excellence, luxury, and durability. Model Evolution W126 Generation: Second generation of the S-Class (W126) produced from 1979 to 1991. The 1991 model year represents the final iteration of this highly successful platform. Production Production Period: W126: 1979-1991 Significant Updates For 1991: The 1991 model year saw continued refinement of...