Segment:
Full-size Luxury Sedan
Brand Reputation:
Known for engineering excellence, durability, and luxury features.
Key Competitors:
BMW 7 Series, Jaguar XJ, Cadillac DeVille
Vehicle Usp:
Spacious interior, refined ride, powerful V8 engine, advanced (for its time) safety and comfort features.
Target Audience:
Mercedes-Benz owners, independent repair shops, automotive enthusiasts, DIY mechanics.
Primary Coverage:
Complete Factory Service and Repair
Specific Sections Mentioned:
Engine, Brakes, Suspension, Seats, Exterior Trim
Estimated Page Count:
Extensive (typical factory manuals exceed 1000 pages)
Type:
Factory Workshop Service Repair Manual
Digital Format:
HTML/Flash menu with PDF content
Powertrain:
Engine mechanical, fuel system, ignition system, cooling system, lubrication system, exhaust system, transmission (automatic)
Chassis:
Suspension (front and rear), steering system, braking system (hydraulic, ABS), wheels and tires
Electrical:
Vehicle electrical system, charging system, starting system, lighting system, instrument cluster, comfort modules, electronic control units (ECUs)
Body:
Body construction, interior trim, exterior trim, seats, doors, windows, HVAC system, body hardware
Maintenance:
Scheduled maintenance, fluid changes, filter replacements, inspections
Repair And Rebuild:
Engine overhaul, transmission rebuild, brake component replacement, suspension component replacement, electrical system diagnostics and repair
Diagnostics:
Troubleshooting guides, fault code interpretation (where applicable for the era), diagnostic procedures for various systems
Depth:
Comprehensive, covering everything from routine maintenance to complete component rebuilds, suitable for professional technicians and advanced DIYers
Digital Interface:
HTML/Flash menu for navigation
Document Format:
PDF (for detailed repair procedures and diagrams)
Printability:
High-resolution, printable pages
Digital Access:
Downloadable digital file (no physical book)
Digital Readability:
Optimized for screen viewing and printing
Operating Systems:
Windows (95, 98, ME, XP, Vista, 7), Linux, macOS
Displacement:
4.2 liters (4196 cc)
Horsepower:
Approx. 200-220 hp (depending on year and specific tuning)
Torque:
Approx. 240-250 lb-ft (depending on year and specific tuning)
Fuel Injection:
Bosch K-Jetronic (CIS) or KE-Jetronic (CIS-E) with electronic timing control
Ignition System:
Electronic ignition (e.g., Bremi or Bosch distributors)
Oil Capacity:
Approx. 8.0 liters (with filter)
Coolant Capacity:
Approx. 12.0 liters
Transmission Type:
4-speed Automatic (e.g., 4G-TRONIC)
Optional Transmission:
None offered for 420SEL in this period.
Transmission Control:
Hydraulic control with electronic assistance for smoother shifts.
Transmission Fluid Type:
MB 236.1 or equivalent ATF (e.g., Dexron II/III, check specific manual)
Crash Test Era:
Pre-modern standardized testing, but known for robust body structure.
ABS:
Anti-lock Braking System (ABS) standard on later models/optional earlier
Traction Control:
ASR (Acceleration Skid Control) may be available on later models, often electronically controlled
Airbags:
Driver's airbag became standard during this generation's run (introduced 1981, widely adopted later).
Seatbelts:
Pretensioners for front seatbelts
Structure:
Reinforced passenger cell, crumple zones
Audio System:
Factory-installed Becker or Blaupunkt AM/FM stereo with cassette player. Optional CD changer availability on later models.
Climate Control:
Automatic climate control (optional on some trims/early models, standard on SEL).
Cruise Control:
Standard cruise control system.
Memory Seats:
Power adjustable front seats with memory function (often included on SEL).
Antenna System:
Power-operated antenna, often integrated into the rear pillar.
Oil Change Interval:
Typically 10,000-15,000 km or 12 months (consult manual for exact spec).
Major Service Interval:
e.g., 50,000-100,000 km for spark plug replacement, transmission service, etc.
Engine Oil Spec:
API SG/SH, ACEA A2/A3, viscosity typically 10W-40 or 15W-40 (check manual for ambient temp suitability)
Coolant Type:
Glycol-based antifreeze (MB 325.0 or equivalent)
Brake Fluid Type:
DOT 3 or DOT 4 (ensure compatibility with ABS if equipped)
Common Wear Items:
Ignition components (distributor cap, rotor, wires), fuel distributor and accumulator (K-Jetronic), fuel pumps, vacuum lines, OVP relay (if equipped), climate control servo motors.
Body Corrosion:
Susceptible to rust in common areas like wheel wells, rocker panels, and battery tray areas, especially in humid climates.
Electrical Gremlins:
Older wiring harnesses can degrade, leading to intermittent electrical issues. Check fuse box connections.
Brand Focus:
Long history of luxury automotive manufacturing, pioneering safety and engineering.
W126 Introduction:
W126 generation introduced in 1979 as a successor to the W116 S-Class.
Facelift Updates:
Significant facelift occurred in 1985, introducing revised bumpers, side mouldings, and improved aerodynamics.
420Sel Introduction:
The 4.2L V8 (M116) engine was introduced as part of the facelift, offering a balance of performance and efficiency.
Production Period:
W126 production ran from 1979 to 1991.
Manufacturing Location:
Sindelfingen, Germany
