🏷️ Basic Information

Make:

Mercedes-Benz

Model:

S-Class

Chassis Code:

W140

Model Range Name:

S-Class

Market Segment:

Full-size Luxury Sedan

Product Name Identifier:

Mercedes-Benz Model 140 STAR Classic Official Service Repair Manual

Manual Type Identifier:

Workshop Service Manual

👋 Introduction

Positioning:

The Mercedes-Benz W140 S-Class represented the pinnacle of automotive engineering and luxury for its era, competing with other ultra-luxury sedans like the BMW 7 Series (E38), Lexus LS (XF20), and Jaguar XJ (XJ40/X300).

Key Competitors:

BMW 7 Series (E38), Lexus LS 400 (XF20), Audi A8 (D2), Jaguar XJ (X300), Cadillac DeVille.

Engineering Excellence:

Known for its robust build quality, advanced technology for its time, and smooth, powerful drivetrains.

Design Evolution:

Characterized by its imposing presence, sophisticated aerodynamics, and iconic double-glazing for reduced cabin noise.

Professional Resource:

This manual is an essential tool for owners, independent mechanics, and enthusiasts seeking to maintain and repair their W140 S-Class with factory-level accuracy and detail.

📋 Manual Details

Primary Coverage:

Complete mechanical and electrical systems of the Mercedes-Benz W140 S-Class

Body And Chassis Coverage:

Body panels, chassis components, suspension, steering, brakes, and exhaust systems

Powertrain Coverage:

Engine (M119, M120, OM603, OM606), transmission (automatic and manual where applicable), fuel system, cooling system, lubrication system

Electrical Coverage:

Wiring diagrams, electrical component testing, control modules (ECU, ABS, SRS), lighting, instrumentation, and comfort systems

HVAC Coverage:

Automatic climate control system diagnosis and repair, refrigerant handling

Interior Coverage:

Interior trim, seats, and associated mechanisms

Estimated Page Count:

Detailed page count not specified, but expected to be extensive (typically 1500+ pages for a complete W140 manual)

Type:

Official Factory Workshop Service and Repair Manual

Language:

English

Format:

PDF (Portable Document Format)

📖 Manual Coverage

Engine Mechanical:

Engine assembly, disassembly, cylinder head, pistons, crankshaft, camshafts, valve train, timing components, seals, and gaskets

Engine Management:

Fuel injection systems (KE-Jetronic, HFM), ignition systems, emissions control, ECU diagnosis and troubleshooting

Transmission Service:

Automatic transmission (722.3, 722.6) service, repair, and overhaul, including valve body, torque converter, and clutch packs. Diesel manual transmission service where applicable.

Suspension System:

Front and rear suspension component replacement, alignment procedures, shock absorbers, springs, control arms, bushings

Steering System:

Power steering system diagnosis and repair, steering gear, tie rods, power steering pump, fluid replacement

Brake System:

Front and rear brake systems, ABS (Anti-lock Braking System) diagnosis and repair, brake pad and rotor replacement, brake fluid flush, hydraulic components

Electrical Systems:

Starter, alternator, battery, lighting circuits, power windows, mirrors, central locking, sunroof, seat adjustment, SRS (Supplemental Restraint System) components and diagnosis

Climate Control:

Automatic climate control system (THERMATIC/THERMOTRONIC) troubleshooting, blower motor, evaporator, condenser, refrigerant lines, diagnostic procedures

Body And Trim:

Body panel removal and installation, door mechanisms, hood and trunk latches, interior trim panel removal, glass replacement

Scheduled Maintenance:

Detailed service schedules based on mileage or time intervals, fluid changes, filter replacements, lubrication points

Diagnostic Troubleshooting:

Systematic diagnostic flowcharts and procedures for common and uncommon issues, symptom-based troubleshooting guides

Repair Procedures:

Step-by-step instructions for component removal, installation, overhaul, and adjustment for all major systems

Wiring Diagrams:

Comprehensive, high-resolution electrical wiring diagrams for all vehicle circuits, including pin-out data for control modules

Specification Tables:

Torque specifications, fluid capacities, clearances, measurements, and wear limits for all serviceable components

Depth:

Comprehensive, from basic maintenance and fluid checks to full engine and transmission rebuilds, and complex electrical diagnostics.

📊 Manual Specifications

File Type:

PDF

Searchability:

Text-searchable PDF content

Print Quality:

High-resolution, suitable for printing individual pages or the entire manual

Binding:

N/A (Digital PDF)

Paper:

N/A (Digital PDF)

⚙️ Engine Specifications

Engines Covered:

M119 (4.2L V8, 5.0L V8), M120 (6.0L V12), OM603 (3.0L Inline-6 Turbo Diesel), OM606 (3.0L Inline-6 Turbo Diesel)

M119 5.0L Hp:

326 hp (approximate)

M119 5.0L Torque:

354 lb-ft (approximate)

M120 6.0L Hp:

408 hp (approximate)

M120 6.0L Torque:

420 lb-ft (approximate)

Gasoline Injection:

Electronic Fuel Injection (EFI) - Bosch HFM (Hot Film Air Mass) and earlier KE-Jetronic variants

Diesel Injection:

Direct Injection, Turbocharged with Intercooler

V8 Engine Code:

M119

V12 Engine Code:

M120

Diesel Inline 6 Engine Code:

OM603/OM606

🔧 Transmission

Primary Automatic:

4-speed Automatic (722.3) on earlier models, 5-speed Automatic (722.6 'NAG1') on later models

Manual Availability:

Rarely offered, primarily on some European market diesel models.

Electronic Control:

Electronic control of transmission shifting (722.6), adaptive shift programs

722.3 Fluid Type:

MB 236.6 Specification Automatic Transmission Fluid (ATF), e.g., Dexron II

722.6 Fluid Type:

MB 236.10 or MB 236.12 Specification ATF, e.g., Mobil ATF 134, Pentosin ATF1

📐 Dimensions

Wheelbase Long Wheelbase:

121.3 inches (3080 mm)

Wheelbase Standard Wheelbase:

118.1 inches (3000 mm)

Overall Length Long Wheelbase:

204.9 inches (5205 mm)

Overall Width:

73.6 inches (1870 mm)

Overall Height:

57.7 inches (1465 mm)

Curb Weight Approx:

4400 - 4800 lbs (2000 - 2180 kg), varies by engine and options

🛡️ Safety Features

NHTSA Rating Era Context:

While formal NHTSA ratings for this era are not directly comparable, the W140 was engineered with a strong emphasis on occupant safety for its time.

ABS:

Standard Anti-lock Braking System (ABS)

Traction Control:

Optional or standard on some variants (ASR - Acceleration Slip Regulation)

Airbags:

Driver and front passenger airbags standard. Side airbags became available on later models.

Srs:

Supplemental Restraint System (SRS) integrated with seatbelt pretensioners.

Construction:

High-strength steel body structure, crumple zones, reinforced passenger cell.

Glass:

Double-glazed side windows for enhanced safety and noise reduction.

💡 Technology Features

Audio System:

High-quality factory sound systems, often with cassette decks, CD changers, and premium speaker options.

Navigation:

Optional factory navigation system (often primitive by modern standards) available on later models.

Cruise Control:

Standard electronic cruise control.

Parking Sensors:

Optional PARKTRONIC parking assist system available on later models.

Analog Systems:

Primarily analog systems with early forms of CAN-bus communication for advanced features.

🔧 Maintenance

Oil Change Interval:

Typically every 7,500-10,000 miles (12,000-16,000 km) or 12 months, depending on driving conditions. Check manual for specific recommendations.

Transmission Service Interval:

Fluid and filter change recommended every 30,000-60,000 miles (50,000-100,000 km) for automatic transmissions.

Coolant Flush Interval:

Every 2-3 years or 30,000 miles (50,000 km).

Engine Oil Type:

API SG/SH or higher, SAE 0W-40, 5W-40, 5W-30, or 10W-40 depending on climate. Consult specific engine requirements in manual.

Coolant Type:

Mercedes-Benz approved coolant (e.g., MB 325.0) - typically a 50/50 mix of antifreeze and distilled water.

Brake Fluid Type:

DOT 3 or DOT 4 low-viscosity brake fluid.

Wiring Harness Degradation:

Known issue with insulation breakdown on engine wiring harnesses, particularly the Motronic harness, leading to engine misfires and running problems.

Headliner Sagging:

Common issue with the headliner fabric detaching from the backing board due to adhesive failure.

Window Regulator Failure:

Window regulators and associated mechanisms can be a point of failure.

Ima Module Failure:

Integrated Motorunit Assistant (IMA) control module, related to climate control and other functions, can fail.

Cooling System Leaks:

Plastic coolant reservoirs, hoses, and seals can degrade over time, leading to leaks.

Door Lock Actuator Failure:

Central locking system actuators can become faulty.

📚 Vehicle History

Mercedes Benz Legacy:

Mercedes-Benz has a long-standing reputation for luxury, engineering, and safety, which the W140 inherited and expanded upon.

W140 Introduction:

Introduced in 1991 as the successor to the W126 S-Class.

W140 Facelift:

Received a facelift in 1994, with subtle exterior revisions and powertrain updates, including the introduction of the 722.6 5-speed automatic transmission.

W140 Discontinuation:

Production ended in 1999, succeeded by the W220 S-Class.

Production Years:

1991-1999

Variants:

Available in standard and long-wheelbase (SEL) versions, and as the CL-Class coupe (C140).

🏆 Awards & Recognition

Industry Recognition:

While specific awards are hard to pinpoint for a single generation, the W140 was universally recognized for its engineering, comfort, and status as a benchmark in luxury automotive design.

Consumer Reports Context:

Often praised for reliability in its powertrain and chassis, though electronics were sometimes noted as a complex area.