🏷️ Basic Information

Make:

Mercedes-Benz

Model:

500 SEL

Model Code:

W126 Series (specific to the long-wheelbase SEL variant)

Generation Designation:

Second Generation W126 (facelifted model)

Engine Code:

M117 (specifically the 5.0L V8 variant)

👋 Introduction

Vehicle Segment:

Full-size luxury sedan

Target Audience:

Affluent buyers seeking unparalleled comfort, performance, and build quality.

Primary Competitors:

BMW 7 Series (E23), Jaguar XJ, Cadillac Fleetwood, Lincoln Continental.

Defining Characteristics:

Exceptional build quality, refined ride, powerful V8 engine, advanced (for its time) features, spacious and luxurious interior, long-wheelbase for enhanced rear passenger comfort.

Manual Value Proposition:

Essential for owners and independent technicians to maintain, diagnose, and repair the Mercedes-Benz 500 SEL to factory specifications, preserving its legacy of engineering excellence.

📋 Manual Details

Covered Regions:

Global (factory specifications applicable worldwide)

Estimated Page Count:

Approximately 1000+ pages (typical for comprehensive factory manuals of this era)

Manual Type:

Factory Service Repair Manual

Language:

English

Format:

Digital (likely PDF, based on common sales practices for older manuals)

📖 Manual Coverage

Engine Systems:

Engine mechanical (cylinder head, block, crankshaft, camshafts, pistons, connecting rods), lubrication system, cooling system, fuel injection system (Bosch K-Jetronic or KE-Jetronic), ignition system, exhaust system, engine management and diagnostics.

Transmission Systems:

Automatic transmission (4-speed 420/500/560 or 5-speed 420/500 in later models), hydraulic control, torque converter, gear selection, shift control, transmission fluid, cooling, and diagnostics.

Drivetrain Systems:

Rear-wheel drive, driveshaft, constant velocity (CV) joints, differential, axle shafts, wheel bearings.

Suspension Systems:

Front independent suspension (double wishbone), rear independent suspension (multi-link/semi-trailing arm), springs (coil), shock absorbers, anti-roll bars, steering knuckles, control arms, bushings.

Brake Systems:

Hydraulic brake system, front and rear disc brakes, anti-lock braking system (ABS), brake calipers, brake rotors, master cylinder, brake lines, parking brake.

Steering Systems:

Recirculating ball steering, power steering system, steering gear, steering column, steering wheel, tie rods, power steering pump and reservoir.

Electrical Systems:

Battery, alternator, starter motor, ignition switch, lighting system (headlights, taillights, interior lights), fuses, relays, wiring diagrams for all circuits, instrument cluster, engine control unit (ECU), power accessories.

Climate Control Systems:

Manual and automatic climate control systems (Klima-Automatik), HVAC unit, blower motor, evaporator, condenser, refrigerant lines, controls, actuators.

Safety Systems:

Seat belts (front and rear), crumple zones, structural integrity, early driver assistance (e.g., limited ABS functionality).

Bodywork And Trim:

Body shell construction, body panels, doors, hood, trunk lid, bumpers, exterior trim, weatherstripping, interior trim panels, seats, upholstery, headliner.

Maintenance Procedures:

Oil and filter changes, air filter replacement, spark plug replacement, fluid level checks and top-offs (coolant, brake fluid, power steering fluid, transmission fluid), drive belt inspection and replacement, battery maintenance.

Diagnostic Procedures:

Troubleshooting guides for common issues, diagnostic trouble codes (DTCs) where applicable for early ECUs, fuel injection system diagnostics, ignition system diagnostics, electrical system fault finding.

Repair Procedures:

Engine overhaul (head gasket replacement, piston and ring replacement, bearing replacement), transmission overhaul or replacement, brake system component replacement (rotors, pads, calipers, lines), suspension component replacement (shocks, bushings, ball joints), steering system repairs, electrical component replacement (alternator, starter, ignition coil), HVAC system repairs.

Component Replacement:

Detailed step-by-step instructions for removing and installing all major and minor components across all vehicle systems.

Specifications And Tolerances:

Precise torque specifications for fasteners, critical clearances, wear limits, and diagnostic specifications for all components.

Depth Of Coverage:

Comprehensive: Covers from basic preventive maintenance to complete engine and transmission rebuilds, including detailed electrical troubleshooting and chassis component overhauls.

📊 Manual Specifications

Digital Format:

PDF

Digital Reproduction Quality:

High-resolution scans of original factory documentation, ensuring clarity of text, diagrams, and illustrations.

Original Binding Type:

Multiple volumes, typically ring-bound or sectioned for ease of use by technicians.

Original Paper Type:

High-quality, durable paper stock designed for workshop environments.

⚙️ Engine Specifications

Engine Type:

V8, SOHC (Single Overhead Camshaft) per bank

Displacement:

4973 cc (303.5 cubic inches)

Bore X Stroke:

94.5 mm x 85.0 mm

Compression Ratio:

8.3:1 or 9.2:1 depending on market and specific variant

Horsepower Net SAE:

Approximately 230-240 hp @ 4750 rpm (varies by market and specific tuning)

Torque Net SAE:

Approximately 280-285 lb-ft @ 3000 rpm (varies by market and specific tuning)

Fuel Delivery:

Bosch CIS (Continuous Injection System) or CIS-E (Electronic) Fuel Injection

Fuel Type:

Unleaded gasoline (Premium Octane recommended)

Oil Capacity W Filter:

8.0 Liters (8.5 US Quarts)

Coolant Capacity:

12.0 Liters (12.7 US Quarts)

Coolant Type Specification:

Mercedes-Benz Specification 325.0 (typically a silicate-free, long-life antifreeze).

🔧 Transmission

Transmission Type:

4-speed Automatic Transmission

Optional Transmission Availability:

Rarely offered in 500 SEL models, but some markets might have had a 5-speed option, though more common on the 420 SEL or 560 SEL.

Torque Converter Lockup:

Yes, for improved fuel economy at cruising speeds.

Transmission Fluid Capacity:

Approximately 2.5 Liters (2.6 US Quarts) for torque converter, total system fill significantly higher.

Transmission Fluid Type:

MB Approved Automatic Transmission Fluid (e.g., MB 236.2, or successor specifications like 236.6/236.7 depending on exact transmission variant and service bulletins).

📐 Dimensions

Wheelbase:

Approximately 3080 mm (121.3 inches) for SEL model

Overall Length:

Approximately 5020 mm (197.6 inches) for SEL model

Overall Width:

Approximately 1798 mm (70.8 inches)

Overall Height:

Approximately 1420 mm (55.9 inches)

Front Legroom:

Generous, designed for comfort.

Rear Legroom:

Exceptional due to SEL long wheelbase.

Trunk Volume:

Substantial, designed for touring.

Curb Weight:

Approximately 1750-1850 kg (3850-4070 lbs), depending on equipment.

Gross Vehicle Weight Rating:

Varies by specification, typically around 2300 kg.

Wheelbase Bolt Pattern:

5x112 mm

Standard Tire Size:

Typically 205/65R15 or 215/60R15

Standard Wheel Size:

15-inch alloy wheels

🛡️ Safety Features

Crash Test Data Availability:

Limited official data by modern standards; however, known for robust body structure and passive safety features for its era.

Anti Lock Brakes:

Standard on 500 SEL, Bosch ABS II system.

Airbags:

Driver's side airbag became optional/standard during the W126 lifecycle, likely available on 1984-1985 models as an option.

Seat Belts:

3-point inertia reel seat belts for front and rear occupants.

Body Structure:

Reinforced safety cell, crumple zones, side-impact protection in doors.

💡 Technology Features

Audio System:

Factory fitted Becker AM/FM radio with cassette player, optional CD changer preparation. Analog tuning and control.

Cruise Control:

Standard fitment, electro-mechanical system.

Climate Control:

Optional 'Klima-Automatik' (automatic climate control) providing sophisticated temperature and air distribution management for the period.

Original Connectivity:

No modern connectivity features (Bluetooth, USB, etc.). Analog systems throughout.

Headlight System:

Halogen headlights, electrically adjustable from inside. Often featured integrated fog lamps.

🔧 Maintenance

Oil And Filter Change:

Every 10,000-15,000 km (6,000-10,000 miles) or annually, whichever comes first, using the correct oil specification.

Transmission Fluid Service:

Every 40,000-60,000 km (25,000-40,000 miles) or as per service bulletins, including filter replacement.

Coolant Flush And Replace:

Every 2-3 years or as per service bulletins, using approved coolant.

Spark Plug Replacement:

Every 30,000-50,000 km (20,000-30,000 miles) depending on plug type (e.g., standard, platinum).

Engine Oil Specification:

API SG or higher, ACEA A2-96 or B2-96. Viscosity typically 15W-40 or 10W-40, depending on climate. Refer to owner's manual for exact MB approval numbers (e.g., MB 229.1).

Brake Fluid Specification:

DOT 3 or DOT 4, per Mercedes-Benz specification (e.g., MB 331.0).

Power Steering Fluid Specification:

MB Approved Power Steering Fluid (e.g., MB 236.3) or equivalent Dexron-III/Mercon when specified.

Common Wear Items:

Fuel distributor seals in CIS, vacuum hoses (due to age and heat), timing chain tensioner (potential for failure if not replaced periodically), blower motor resistors, window regulators, door lock actuators, fuel pump relays.

Potential Electrical Issues:

Corrosion in fuse box connections, aging wiring harnesses, failure of climate control modules, though generally reliable for their era.

Chassis And Suspension Wear:

Worn control arm bushings, ball joints, and shock absorbers are common due to high mileage and age.

📚 Vehicle History

Mercedes Benz Legacy:

Renowned for engineering precision, luxury, durability, and technological innovation in automotive design.

W126 Introduction:

Introduced in 1979 as a successor to the W116, the W126 redefined the luxury sedan segment with its aerodynamic design, improved safety, and refined driving dynamics.

W126 Facelift:

The 1981-1985 models represent the initial production run. A significant facelift occurred for the 1986 model year, with styling updates and powertrain improvements (e.g., introduction of the 560 SEL). The 1984-1985 models are part of the pre-facelift, but the 500 SEL was a high-performance variant from the outset.

500 Sel Positioning:

The 500 SEL was positioned as a powerful, yet refined long-wheelbase variant, offering a balance of performance and supreme comfort.

Production Period:

W126 Series: 1979-1991. The 500 SEL was produced for specific markets during this period, with the 1984-1985 timeframe being within its availability.

Manufacturing Location:

Sindelfingen, West Germany

🏆 Awards & Recognition

Car And Driver 10 Best:

The W126 chassis (including the 500 SEL) was a frequent recipient of Car and Driver's '10Best' list in the early to mid-1980s, acknowledging its superior engineering and luxury.

European Car Of The Year:

While not awarded to the 500 SEL specifically, the W126 chassis's design and engineering excellence contributed to Mercedes-Benz's reputation that earned many accolades during this period.

Automotive Engineering Standards:

Built to rigorous German engineering standards, emphasizing durability, safety, and performance.