Segment:
Full-Size Luxury Sedan
Key Competitors:
BMW 7 Series, Lexus LS, Audi A8, Jaguar XJ
Luxury Appointments:
Exceptional ride comfort, high-quality interior materials, advanced features for its era
Engineering:
Robust M119 V8 engine, advanced independent suspension, sophisticated electronic systems
Value Proposition:
Access to detailed factory service information for a premium luxury vehicle
Primary Coverage:
Mechanical, Electrical, Bodywork, Diagnostics
Secondary Coverage:
Maintenance Schedules, Troubleshooting Guides, Wiring Diagrams
Type:
Official Factory Service Manual
Format:
Software (likely PDF or proprietary digital format)
Engine:
4.2L V8 (M119.985), Fuel System (EFI), Ignition System, Cooling System, Exhaust System, Lubrication System
Transmission:
4-Speed Automatic (722.6 '5G-Tronic')
Drivetrain:
Rear Wheel Drive (RWD)
Suspension:
Front: Independent Multi-Link, Rear: Independent Multi-Link, Self-Leveling Suspension (SLS) details
Brakes:
Front: Ventilated Discs, Rear: Ventilated Discs, ABS (Anti-lock Braking System), ESP (Electronic Stability Program)
Steering:
Hydraulic Power Steering, Speed-Sensitive Steering
Electrical:
Charging System, Starting System, Lighting, Instruments, Body Control Modules (BCM), CAN Bus communication (limited)
Climate Control:
Automatic Climate Control (Thermotronic), HVAC System Components
Body:
Body Exterior Panels, Doors, Hood, Trunk, Glass, Upholstery, Body Repair
Safety Systems:
Airbags (Front, Side), Seatbelt Pre-tensioners, Crumple Zones
Maintenance:
Oil Change, Filter Replacement, Fluid Checks and Changes, Spark Plug Replacement, Belt Inspection and Replacement
Troubleshooting:
Diagnostic Trouble Codes (DTCs), Symptom-Based Diagnosis, Component Testing
Repair:
Engine Overhaul, Transmission Rebuild, Suspension Component Replacement, Brake System Repair, Electrical Component Diagnosis and Replacement
Diagnostics:
Scan Tool Procedures (OBD-II), Live Data Interpretation, Component Actuation Tests
Wiring Diagrams:
Comprehensive Electrical Schematics for all Systems
Depth:
Comprehensive Factory Level Detail, Suitable for Professional Technicians and Advanced DIY Enthusiasts
Rebuilds:
Engine and Transmission Rebuild Procedures Included
Calibrations:
Key Component Calibrations (e.g., Throttle Body, ABS Sensors) covered
Software Type:
Digital, likely searchable PDF or proprietary application
Resolution:
High-resolution, suitable for printing
Text Search:
Yes, fully text-searchable
Crash Test Data:
NHTSA/IIHS data for this specific year may be limited; focus on design intent and features.
ABS:
Standard Anti-lock Braking System
Esp:
Standard Electronic Stability Program (from 1997 onwards)
Traction Control:
ASR (Anti-Slip Regulation)
Airbags:
Driver and Passenger Front Airbags, Optional Side Airbags
Seatbelts:
Pre-tensioning Seatbelts with Force Limiters
Body Structure:
High-strength steel chassis with energy-absorbing crumple zones
Audio System:
Factory premium sound system, likely with cassette and optional CD changer. Manual covers basic diagnostics and speaker replacement.
Navigation:
Optional COMAND system (less common on S420, more on V8 and V12 models, and later years).
Cruise Control:
Standard electronic cruise control.
Parking Sensors:
Optional front and rear Parktronic sensors.
Tel System:
Optional cellular telephone integration.
Oil Change Interval:
Every 10,000 miles or 12 months, whichever comes first (using synthetic oil)
Transmission Service:
Every 60,000 miles or 4 years (fluid and filter replacement)
Coolant Service:
Every 30,000 miles or 3 years (using Mercedes-Benz approved coolant)
Spark Plugs:
Every 100,000 miles (Long Life Spark Plugs)
Coolant Type:
Mercedes-Benz Specification 325.0 (Glysantin G48 or equivalent Blue/Green OAT)
Head Gaskets:
While M119 is robust, head gasket leaks can occur due to age/overheating. Manual provides inspection and repair procedures.
Cooling System:
Plastic coolant reservoir brittle, hose degradation, water pump leaks are common. Manual details replacement.
Window Regulators:
Known to fail; manual covers diagnosis and replacement.
Door Locks:
Vacuum-operated door locking system can develop leaks. Manual provides troubleshooting for the system.
Electronics:
Age-related failures in various electronic modules (e.g., EZL, EIS, ABC control modules if equipped on later W140 models, though S420 likely has SLS). Manual covers diagnostic approaches.
Legacy:
Mercedes-Benz has a long-standing reputation for engineering excellence, luxury, and safety.
Generation:
W140 ('S-Class' Generation 1991-1998, facelift in 1994)
Positioning:
The W140 was the flagship sedan, representing the pinnacle of Mercedes-Benz technology and luxury during its production run.
Production Years:
1991-1998
Manufacturing Location:
Sindelfingen, Germany
