Vehicle Class:
Full-size Luxury Sedan
Target Audience:
Affluent buyers seeking ultimate comfort, performance, and prestige
Key Competitors:
BMW 7 Series (E32/E38), Lexus LS 400 (XF10), Rolls-Royce Silver Spirit/Spur
Engine Highlight:
M120 6.0L V12 engine, one of Mercedes-Benz's first production V12s
Technology Highlight:
Advanced (for its time) electronic systems, sophisticated suspension and comfort features
Interior Luxury:
Exceptional build quality, premium materials, spacious and opulent cabin
Owner Empowerment:
Enables owners to confidently perform repairs and maintenance, saving on professional labor costs.
Technical Resource:
Provides the same in-depth information utilized by professional Mercedes-Benz technicians.
Engine:
V12 M120 Engine (including timing, fuel injection, cooling, lubrication, exhaust)
Transmission:
Automatic Transmission (4-speed 4G-TRONIC) and Manual Transmission (less common for SEL, but coverage may exist for commonalities)
Drivetrain:
Rear-wheel Drive, Driveshaft, Axles, Differential
Suspension:
Front and Rear Suspension, Level Control (ADS - Active Damping System), Self-Leveling Suspension
Brakes:
Hydraulic Brake System (ABS), Parking Brake, Brake Fluid Maintenance
Steering:
Power Steering System, Steering Column
Electrical System:
Complete Wiring Schematics, Lighting, Ignition System, Battery, Charging System, Starting System
Climate Control:
Air Conditioning (AC) System, Heating System, Ventilation, Filters
Body And Chassis:
Body Structure, Corrosion Inspection, Water Leakage, Doors, Hood, Sunroof, Soft Top (if applicable to specific trims), Interior Panels
Fuel System:
Fuel Tank, Fuel Pump, Fuel Filter, Fuel Lines, Injection System Components
Routine Maintenance:
Oil and Filter Changes, Fluid Level Checks, Filter Replacements (Air, Fuel, Cabin), Belt Inspections
Engine Repair:
Valve Clearance Adjustment, Injection Timing, Spark Plug Replacement, Engine Mounts, Intake/Exhaust Manifold Seating
Transmission Service:
Fluid and Filter Changes, Fluid Level Corrections, Clutch System Checks
Brake Service:
Brake Fluid Replacement, Pad and Disc Inspection, Parking Brake Adjustment, Brake Testing
Suspension And Steering Service:
Ball Joint Inspection, Level Control Fluid Checks, Wheel Alignment Checks (implied by tire/wheel inspection)
Electrical Diagnostics:
Wiring Diagram Interpretation, Component Testing, Fault Finding
Troubleshooting:
Step-by-step diagnostic procedures for various systems
Rebuilding And Refurbishment:
Procedures for rebuilding major components
Depth:
Comprehensive, covering diagnostics, repair, rebuild, and refurbishment. Equivalent to factory technician information.
Detail Level:
Step-by-step instructions, diagrams, illustrations, and specifications
Displacement:
5987 cc (6.0 Liters)
Bore X Stroke:
89.0 mm x 78.9 mm
Compression Ratio:
10.0:1
Horsepower:
389 hp @ 5200 rpm (approx.)
Torque:
420 lb-ft @ 3800 rpm (approx.)
Fuel Delivery:
Bosch LH-Jetronic Fuel Injection (Multi-point)
Fuel Type:
Premium Unleaded Gasoline (91+ octane recommended)
Engine Oil Type:
MB 229.1 Specification (e.g., 15W-40 or 10W-40)
Engine Oil Capacity:
8.0 Liters (approx. 8.5 US Quarts) with filter
Spark Plugs:
Long-life iridium or platinum type, 2 per cylinder (12 total)
Coolant Type:
Mercedes-Benz Approved Coolant (e.g., G48 or equivalent blue/green type)
Coolant Capacity:
12.0 Liters (approx. 12.7 US Quarts)
Transmission Type:
4-speed Automatic (4G-TRONIC 722.3 or 722.4 series)
Optional Transmission:
N/A for SEL model (typically only automatic offered)
Transmission Features:
Electronically controlled, Torque Converter Lock-up, Comfort/Sport Modes
Transmission Fluid Type:
MB 236.1 Specification (e.g., Dexron II or equivalent)
Transmission Fluid Capacity:
7.5 Liters (approx. 7.9 US Quarts) for fluid and filter change
Audio System:
Premium sound system (e.g., Becker or Bose), Cassette deck, Radio
Adaptive Damping:
ADS (Active Damping System) for adjustable ride comfort
Stability Control:
ASR (Acceleration Skid Control)
Climate Control Features:
Dual-zone automatic climate control, HEPA cabin air filters
Power Features:
Power-adjustable seats with memory, power windows, power sunroof, power mirrors, power door locks
Oil Change Interval:
Typically every 15,000 km (9,300 miles) or 12 months, whichever comes first (refer to manual for exact).
Transmission Service Interval:
Every 40,000-60,000 km (25,000-37,000 miles) for fluid and filter change.
Spark Plug Replacement Interval:
Long-life spark plugs, often rated for 100,000 km (60,000 miles) or more.
Common Issues Early W140:
Hydraulic system leaks (suspension, self-leveling), cooling system issues (plastic components), some electrical gremlins, early V12 complexity.
Common Issues General:
Door seal degradation, window regulator issues, catalytic converter failure (due to age/mileage).
Heritage Summary:
Mercedes-Benz has a long history of engineering luxury, performance, and safety since its inception.
W140 Introduction:
The W140 generation replaced the W126 S-Class and was a significant technological leap, setting new standards for luxury sedans.
W140 Design Philosophy:
Emphasis on quietness, ride comfort, safety, and sophisticated technology.
Production Years:
1991-1998 (W140 generation)
Manufacturing Location:
Sindelfingen, Germany
