Vehicle Segment:
Ultra-luxury full-size sedan
Target Audience:
Affluent individuals seeking supreme comfort, advanced technology, and powerful performance.
Primary Competitors:
BMW 7 Series (E38), Lexus LS400, Rolls-Royce Silver Spirit, Bentley Continental.
Engine Offering:
Exclusive V12 engine, setting a benchmark for smoothness and power in its class.
Technology Suite:
Introduction of advanced features like CAN bus, double-glazed windows, soft-close doors, and sophisticated climate control.
Design Philosophy:
Emphasis on robust engineering, safety, and unparalleled ride comfort, often referred to as the 'Schwabian tank' for its build quality.
Engine And Powertrain:
Complete coverage of the M120 V12 engine, including fuel injection, ignition, cooling, lubrication, emissions, and exhaust systems.
Transmission:
Detailed information on the 722.6 (5G-TRONIC) 5-speed automatic transmission, including operation, diagnosis, overhaul, and fluid specifications.
Chassis And Suspension:
Covers all aspects of the W140 chassis, including independent suspension (front and rear), hydraulic leveling system (NIVOMAT), steering components, and chassis lubrication.
Brakes:
Comprehensive data on the anti-lock braking system (ABS), brake fluid specifications, brake pad replacement, rotor resurfacing/replacement, and parking brake.
Electrical System:
Extensive coverage of the vehicle's electrical system, including wiring diagrams, fuse box layouts, battery maintenance, alternator, starter, lighting, power accessories, and diagnostic procedures.
Body And Interior:
Details on body panel removal and installation, door mechanisms, window regulators, climate control system (HVAC), interior trim, and sound insulation.
Climate Control:
In-depth coverage of the automatic climate control (ACC) system, including refrigerant handling, component testing, and diagnostic codes.
Scheduled Maintenance:
Detailed maintenance schedules for various mileage/time intervals, including oil changes, filter replacements, fluid checks, and inspections.
Diagnostic Troubleshooting:
Systematic troubleshooting guides for common and uncommon issues, with symptom-based diagnosis and step-by-step repair procedures.
Component Replacement:
Clear, illustrated instructions for replacing virtually every major and minor component on the vehicle.
Engine Overhaul:
Complete procedures for engine disassembly, inspection, repair, and reassembly, including torque specifications and clearances.
Transmission Overhaul:
Detailed overhaul procedures for the 5G-TRONIC transmission, including internal component replacement and calibration.
Electrical Diagnostics:
Step-by-step diagnostic procedures for electrical faults, including use of multimeters, oscilloscopes, and factory diagnostic tools.
Suspension And Steering Repair:
Procedures for replacing suspension components, steering rack, tie rods, and alignment specifications.
Depth Of Coverage:
Comprehensive, covering everything from basic fluid changes to complete engine and transmission rebuilds.
Diagnostic Capability:
Includes detailed diagnostic trouble codes (DTCs) and testing procedures for various electronic control modules (ECMs).
Specifications And Tolerances:
Provides all necessary torque specifications, clearances, fluid capacities, and performance data.
Crash Test Performance:
Excellent for its era; W140 platform was engineered with a focus on structural integrity and occupant protection.
ABS:
Standard Anti-lock Braking System (ABS).
Traction Control:
Standard Acceleration Slip Regulation (ASR).
Airbags:
Driver and front passenger airbags (dual-stage).
Seatbelts:
Pretensioning front seatbelts, rear seatbelts.
Chassis Structure:
High-strength steel construction, crumple zones.
Oil Change Interval:
Every 10,000 miles or 12 months (whichever comes first), using synthetic oil.
Transmission Fluid Change:
Every 30,000-60,000 miles (consult manual for specific recommendations and procedures).
Coolant Change Interval:
Every 2-3 years or 30,000 miles.
Engine Oil Spec:
MB 229.1 or higher (e.g., Mobil 1 0W-40, Castrol 5W-40).
Engine Oil Capacity:
Approx. 8.5 Liters (with filter).
Transmission Fluid Spec:
MB 236.8 or MB 236.10 (for 722.6 transmission).
Coolant Spec:
Mercedes-Benz approved coolant (e.g., ZEREX G-48).
Common Problems:
Head gasket leaks (M120), distributorless ignition module (CDI) failure, window regulator failures, vacuum leak issues, corrosion on wiring harnesses, biodegradable wiring insulation degradation.
Recommended Preventative:
Regular inspection of wiring harnesses for insulation degradation, checking for vacuum leaks, proactive replacement of vacuum-operated components.
Mercedes Benz Legacy:
Mercedes-Benz has a long-standing reputation for engineering excellence, luxury, and safety, dating back to the late 19th century.
W140 Introduction:
The W140 S-Class was introduced in 1991 as a successor to the W126 S-Class, representing a significant leap in size, technology, and luxury.
W140 Facelift:
Received a facelift in 1994, with minor styling updates and powertrain improvements.
Production Years:
1991-1998
Manufacturing Location:
Sindelfingen, Germany
