🏷️ Basic Information Identification Make: Mercedes-Benz Model: 420 SEL Chassis Code: W126 Generation Generation Designation: Second Generation W126 Production Years For Generation: 1979-1991 Codes Model Code: 126.034 👋 Introduction Market Position Market Segment: Full-size Luxury Sedan Target Audience: Owners of Mercedes-Benz 420 SEL (W126), Independent Repair Shops, Automotive Enthusiasts Competitive Analysis Key Competitors Era: BMW 7 Series (E23/E32), Audi V8 quattro, Jaguar XJ, Cadillac Fleetwood, Lincoln Continental Key Features Vehicle Hallmarks: Exceptional build quality, refined ride comfort, powerful V8 engine, sophisticated engineering, advanced safety features for its time. Manual Value Proposition Dealer Equivalence: Same Repair Service manual used by local dealers Access Method: Instant Download 📋 Manual Details Coverage Areas Covered Years: 1986, 1987, 1988, 1989, 1990, 1991 Specific Models Covered: Mercedes-Benz 420 SEL (W126) Page Count Estimated Page Count: Extensive (Factory Original Content) Manual Type Manual Type: Factory Service and Repair Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine Systems: Engine Mechanical, Fuel Injection (Bosch KE-Jetronic), Ignition System, Cooling System, Lubrication System, Emission Control Systems Transmission Drivetrain: Automatic Transmission (722.3/722.4), Driveshaft, Rear Axle, Differential Chassis Suspension: Front Suspension, Rear Suspension, Steering System, Level Control System (Hydropneumatic), ADS (Automatic Differential Suspension), 4MATIC All-Wheel Drive System (if applicable to specific sub-models/options) Braking System: Hydraulic Brake System, Anti-lock Braking System (ABS), Parking Brake Electrical System: Battery, Charging System, Starting System, Lighting, Instrumentation, Fuses, Relays, Electronic Control Units (ECUs), Power Accessories (Windows, Locks, Mirrors, Sunroof, Seats), Climate Control Electronics, Windshield Wipers/Washers Body Interior: Body Structure, Exterior Panels, Doors, Hood, Trunk Lid, Bumpers, Interior Trim, Seats, Headliner, Convertible Top (if applicable to other W126 variants, though less common for 420SEL), Audio System, Climate Control Unit Procedures Included Maintenance Procedures: Oil Changes, Filter Replacements (Oil, Air, Fuel), Fluid Level Checks and Top-offs (Coolant, Power Steering, Brake, Transmission, Differential), Belt Inspections and Replacements, Spark Plug Replacement, Valve Clearance Adjustment, Cooling System Flush and Refill, Brake Fluid Flush and Bleed, Air Filter Cleaning/Replacement, Lubrication Points Diagnostic Procedures: Troubleshooting Guides, Diagnostic Trouble Codes (DTCs) if applicable to onboard diagnostics, Inspection Procedures for all systems, Component Testing Repair Procedures: Engine Component Removal and Installation (e.g., cylinder heads, fuel injectors, manifolds), Transmission Overhaul and Repair, Suspension Component Replacement (shocks, struts, bushings, ball joints), Brake Component Replacement (pads, rotors, calipers, lines), Electrical Component Diagnosis and Replacement, Steering System Repair, Body Panel Repair and Alignment Adjustment Procedures: Idle Speed Adjustment, Injection Timing Adjustment, Parking Brake Adjustment, Clutch Adjustment (if manual transmission equipped, unlikely for 420SEL), Steering Alignment Specifications Technical Depth Technical Depth: Comprehensive: From basic maintenance and fluid changes to advanced engine diagnostics, transmission overhauls, and electrical system troubleshooting. Includes detailed diagrams, torque specifications, and step-by-step repair instructions. 📊 Manual Specifications File Format File Format: PDF Searchability: Fully searchable text Print Quality Printability: All pages printable Binding Type Binding Type: Digital Download (No physical binding) Paper Type Paper Type: N/A (Digital) File Quality File Quality: Real files, not scans ⚙️ Engine Specifications Primary Engine Engine Code: M116 (4.2L V8) Engine Type: Naturally Aspirated V8 SOHC Displacement: 4.2 Liters (4196 cc) Performance Horsepower Approx: 180-200 hp (depending on market and emission controls) Torque Approx: 235-250 lb-ft Fuel System Fuel Delivery System: Bosch KE-Jetronic Electronic Fuel Injection Recommended Fuel: Premium Unleaded Gasoline (91+ Octane) Maintenance Related Valve Adjustment Type: Hydraulic Valve Lifters (typically no adjustment needed unless issues arise) Air Filter Type: Paper Element or Metal Reinforced Element (depending on specific component) 🔧 Transmission Standard Transmission Transmission Type: 4-Speed Automatic Transmission Transmission Model Code: 722.3 or 722.4 Optional Transmission Optional Transmission Type: N/A for 420 SEL models Features Transmission Features: Comfort-oriented shift points, selectable modes (e.g., Economy/Sport, though less common on early models). Maintenance Related Transmission Fluid Type: MB 236.3 Specification (e.g., Dexron II or equivalent) Transmission Fluid Capacity: Approximately 8 Liters (17 pints) for complete fluid change, less for drain and fill. 📐 Dimensions Exterior Body Style: Long Wheelbase Sedan (SEL) Wheelbase Mm: 2935 mm (115.6 in) Length Mm: 5075 mm (199.8 in) Weights Curb Weight Kg Approx: 1750 - 1850 kg (3858 - 4079 lbs) 🛡️ Safety Features Ratings Crash Test Information: Specific ratings from era are not directly comparable to modern standards. Known for robust construction. Active Features Active Safety Features: Anti-lock Braking System (ABS), Power-Assisted Steering Passive Features Passive Safety Features: Reinforced safety cage, crumple zones, driver's airbag (standard from late 1980s), front seatbelt pretensioners, side-impact protection. 💡 Technology Features Infotainment Audio System: Factory premium sound system, often with cassette player and multi-speaker setup. Antenna System: Power-operated retractable antenna mast. Driver Assistance Cruise Control: Standard factory cruise control. Climate Control: Automatic Climate Control (Klimaautomat) with electronic temperature regulation and air recirculation. Connectivity Original Phone System: Optional integrated car phone systems were available in some markets. Other Features Headlamp Wipers: Headlamp washer/wiper system (common feature on W126). 🔧 Maintenance Service Intervals Oil Change Interval: Every...