🏷️ Basic Information Identification Make: Mercedes-Benz Model: 350 SD Turbo Year: 1991 Codes Chassis Code: W126 Engine Code: OM603.960 👋 Introduction Market Position Market Position: The 1991 Mercedes-Benz 350 SD Turbo (W126 chassis) represented the pinnacle of diesel luxury sedans, competing with other high-end marques. It offered exceptional build quality, comfort, and the rugged reliability associated with Mercedes-Benz diesel powertrains. Competitive Analysis Competitive Analysis: Competitors included models from BMW (e.g., 7 Series diesel variants where available), Jaguar, and other premium manufacturers. The 350 SD Turbo distinguished itself with its robust diesel engine and characteristic Mercedes-Benz ride and build quality. Key Features Key Features: Turbocharged inline-six diesel engine, luxurious interior appointments, advanced safety features for its era (e.g., ABS), robust construction, excellent long-distance cruising capability, and a legendary Mercedes-Benz diesel reputation for durability. 📋 Manual Details Coverage Areas Coverage Areas: Full factory service and repair for 1991 Mercedes-Benz 350 SD Turbo (W126 chassis) Page Count Page Count: Estimated 1000+ pages (typical for comprehensive factory manuals of this era) Manual Type Manual Type: Factory Service Manual / Repair Manual Language Language: English Format Format: Digital (PDF), likely searchable and printable Digital Format Benefits: Searchable text for quick information retrieval, zoomable diagrams, easily printable specific sections. 📖 Manual Coverage Systems Covered Systems Covered: Engine (OM603.960), Fuel System, Diesel Injection System, Turbocharger, Cooling System, Lubrication System, Exhaust System, Transmission (4-speed Automatic), Drivetrain, Suspension (Front & Rear), Steering, Brakes (ABS), Electrical System (Wiring Diagrams, Components), Climate Control (HVAC), Body & Chassis, Interior Trim, Diagnostic Procedures, Troubleshooting Electrical System Details: Complete wiring diagrams for all vehicle systems, component location charts, troubleshooting guides for electrical faults, fuse and relay identification. Procedures Included Procedures Included: Routine maintenance, component removal and installation, major overhauls, diagnostic troubleshooting, electrical system repair, brake system service, suspension and steering alignment, fuel system diagnosis and repair, turbocharger servicing, climate control system repair, body panel alignment and repair, interior component service Engine Performance Tuning: While not a performance tuning manual, it covers correct adjustment of injection timing and basic engine settings for optimal performance and emissions. Wheel Alignment Specifications: Provides front and rear wheel alignment specifications (caster, camber, toe) for proper handling and tire wear. Technical Depth Technical Depth: Comprehensive from basic maintenance and fluid changes to complete engine and transmission rebuilds, including detailed diagnostic flowcharts and specifications Diagnostic Troubleshooting: Detailed flowcharts for diagnosing common and uncommon issues, covering symptoms, probable causes, and corrective actions. 📊 Manual Specifications File Format File Format: PDF Print Quality Print Quality: High-resolution scans of original factory documents, ensuring clarity of text and diagrams Binding Type Binding Type: N/A (Digital Format) Paper Type Paper Type: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Primary Engine: 3.5L Inline-6 Turbocharged Diesel (OM603.960) Performance Horsepower: Approximately 134 hp @ 4000 rpm (varies slightly by market) Torque: Approximately 217 lb-ft @ 2400 rpm (varies slightly by market) Fuel System Fuel System: Bosch inline mechanical fuel injection pump, indirect injection Turbocharger Turbocharger Details: Garrett AiResearch turbocharger, air-to-air intercooler Bore Stroke Bore Stroke: 91.0 mm x 108.6 mm Compression Ratio Compression Ratio: 22.0:1 Engine Management Engine Management: Electronic diesel control (EDC) system for fuel injection timing and quantity Engine Disassembly Instructions: Manual provides detailed step-by-step procedures for engine disassembly, including torque specifications, special tool requirements, and component clearances. Cooling System Cooling System Description: Pressurized system with belt-driven water pump, radiator, thermostat, and expansion tank. Features a viscous fan clutch for temperature-dependent cooling. Lubrication System Lubrication System Description: Forced lubrication via engine-driven oil pump, oil filter, and oil cooler (if equipped). Includes oil pressure specifications and troubleshooting. 🔧 Transmission Standard Standard Transmission: 4-speed Automatic Transmission (722.4) Optional Optional Transmission: N/A for the 350 SD Turbo model Features Transmission Features: Lock-up torque converter, driver-selectable modes (e.g., Economy/Sport) Fluid Type Transmission Fluid Type: Mercedes-Benz Specification 236.1 (e.g., Dexron II compatible) 📐 Dimensions Exterior Wheelbase: 112.8 inches (2865 mm) Length: 192.1 inches (4880 mm) Width: 70.5 inches (1790 mm) Height: 55.7 inches (1415 mm) Front Track: 60.1 inches (1527 mm) Rear Track: 59.2 inches (1503 mm) Ground Clearance: Approximately 6.0 inches (150 mm) unladen. Weights Curb Weight: Approximately 3900 lbs (1770 kg) Gross Vehicle Weight Rating: Approximately 4960 lbs (2250 kg) Towing Capacity: Not typically specified for this luxury sedan; focus on passenger comfort and cargo. 🛡️ Safety Features Ratings Safety Ratings: NHTSA and IIHS ratings from this era are less standardized, but the W126 chassis was known for its robust safety cell and energy-absorbing crumple zones. Active Features Active Features: Anti-lock Braking System (ABS) Passive Features Passive Features: Dual front airbags, energy-absorbing steering column, reinforced passenger cell, side-impact protection (door beams), three-point seat belts with pretensioners Seat Belts: Front and rear three-point seat belts, front seat belt height adjustment. Brake System Brake System Type: Four-wheel disc brakes with ABS 💡 Technology Features Infotainment Infotainment System: Factory fitted AM/FM stereo...