🏷️ Basic Information

Make:

Mercedes-Benz

Model:

S320

Year:

1997

Chassis Code:

W140

Engine Code:

M104.990

👋 Introduction

Positioning:

A premium luxury sedan, the S320 represented the pinnacle of Mercedes-Benz engineering and comfort for its era.

Competitors:

Competed with other high-end luxury sedans such as the BMW 7 Series, Lexus LS, and Audi A8.

Luxury:

Renowned for its sophisticated ride, high-quality interior materials, advanced features, and quiet cabin.

Technology:

Introduced or refined many automotive technologies that are commonplace today.

User Base:

Suitable for professional mechanics, DIY enthusiasts, and owners seeking to understand their vehicle.

Cost Savings:

Enables owners to perform repairs themselves or to have informed discussions with service technicians, potentially saving significant costs.

📋 Manual Details

Primary Coverage:

Service and Repair

Scope:

All models and configurations for the 1997 S320

Estimated Pages:

> 1000

Type:

Service & Repair Manual

Language:

English

Format:

Digital (PDF)

Compatibility:

Works on all computers using Adobe Acrobat reader

Operating Systems:

Mac, Windows

Print Capability:

Printable pages as needed

📖 Manual Coverage

Powertrain:

Engine mechanical, fuel system, ignition system, cooling system, exhaust system

Drivetrain:

Transmission (automatic), driveshaft, differential, axles

Chassis:

Suspension (front and rear), steering system, braking system (including ABS), wheels and tires

Electrical:

Complete wiring schematics, starting and charging system, lighting, instrumentation, body electronics, power accessories (windows, locks, seats), climate control electronics, SRS (Airbag) system

Body:

Exterior body panels, interior trim, doors, windows, locks, glass, sunroof, seat mechanisms

Maintenance:

Oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt inspection and replacement, brake pad replacement, general inspections

Troubleshooting:

Diagnostic procedures for common faults, symptom-based troubleshooting guides, error code interpretation

Repair:

Detailed step-by-step repair instructions for all major components and systems, including engine internal repairs, transmission overhaul, suspension component replacement, brake system repairs, electrical component diagnosis and replacement

Installation:

Instructions for replacing various components and parts

Depth:

Comprehensive, covering from basic maintenance to advanced diagnostics and complete rebuilds

Detail Level:

Includes detailed part layouts, torque specifications, clearances, and diagnostic flowcharts

📊 Manual Specifications

File Type:

PDF

Searchability:

Likely searchable text within PDF sections

Resolution:

High quality, suitable for clear printing of diagrams and text

Binding:

N/A (Digital Format)

Paper:

N/A (Digital Format)

Structure:

Over 70 separate PDF sections, likely organized by system or component

⚙️ Engine Specifications

Configuration:

Inline-6 (Straight-6)

Displacement:

3.2 Liters (3199 cc)

Valvetrain:

DOHC (Dual Overhead Camshafts), 4 valves per cylinder

Horsepower:

Approx. 228 hp @ 5500 rpm

Torque:

Approx. 232 lb-ft @ 3750 rpm

Induction:

Electronic Fuel Injection (EFI)

Fuel Type:

Unleaded Gasoline (Premium Recommended)

Type:

Pressurized Liquid Cooling System

Oil Capacity:

Approx. 8.0 Liters (8.5 US Quarts) - refer to manual for exact capacity and specific oil grade

🔧 Transmission

Type:

4-Speed Automatic Transmission (722.6 '5G-TRONIC' variant introduced later in the W140 generation, but the 1997 S320 typically uses the 4-speed)

Modes:

Standard and Economy (E) modes

Fluid Type:

Mercedes-Benz Automatic Transmission Fluid (ATF) - e.g., MB-Approval 236.1 or 236.3 for the 4-speed; MB-Approval 236.10 or 236.14 for the 5-speed. Consult manual for exact specification.

📐 Dimensions

Length:

Approx. 5113 mm (201.3 inches)

Width:

Approx. 1886 mm (74.3 inches)

Height:

Approx. 1434 mm (56.5 inches)

Curb Weight:

Approx. 1800-1900 kg (3968-4189 lbs) - varies by equipment

🛡️ Safety Features

Crash Test Data:

While specific NHTSA/IIHS ratings for 1997 may be limited, the W140 chassis was engineered with advanced safety structures for its time.

Airbags:

Driver and front passenger airbags (SRS)

Seatbelts:

Pre-tensioning seatbelts

Construction:

Reinforced body structure, crumple zones

ABS:

Anti-lock Braking System (ABS)

Traction Control:

Acceleration Slip Regulation (ASR) standard on some models/markets

💡 Technology Features

Audio System:

Premium sound system, often with Bose components, AM/FM/Cassette/CD capabilities depending on original options.

Navigation:

Optional factory navigation system available on some models.

Cruise Control:

Standard cruise control.

Parking Assistance:

Optional rear park assist (Parktronic) not commonly found on this year, more prevalent in later models.

Telematics:

Early forms of telematics or cellular phone integration might be present as options.

Climate Control:

Dual-zone automatic climate control (Thermotronic), often with air filtration.

Seats:

Power-adjustable front seats with memory, heated seats, multi-contour seats available as options.

🔧 Maintenance

Oil Change Interval:

Typically every 7,500 to 10,000 miles (12,000 to 16,000 km) or annually, depending on driving conditions and oil quality. Refer to manual for precise intervals and service 'A'/'B' indicators.

Major Service:

Key service intervals for spark plugs, transmission fluid, coolant, and brake fluid typically fall between 30,000 and 60,000 miles. Consult the manual for detailed schedule.

Engine Oil:

API SG or higher, viscosity 0W-30, 5W-30, 5W-40, or 10W-40 depending on ambient temperature. MB-Approval 229.1, 229.3, or 229.5 recommended for best performance and longevity. Consult manual for exact specification.

Coolant:

Ethylene Glycol based antifreeze. Mercedes-Benz specification 325.0 (blue/green) or 326.0 (phosphate-free). Typically a 50/50 mix with distilled water.

Brake Fluid:

DOT 3 or DOT 4, per MB-Approval 331.0 or 332.0.

Common Problems:

Head gasket sealing issues (especially with early M104 variants), vacuum line deterioration, biodegradable wiring harness insulation degradation, ABS/ASR system faults, window regulator failures, SRS system warning lights, sagging headliner, door lock actuator failures, blower motor resistor issues.

Maintenance Focus:

Due to the complexity and age, regular preventative maintenance and addressing minor issues before they escalate is critical.

📚 Vehicle History

Mercedes Benz Legacy:

Mercedes-Benz has a long-standing reputation for building robust, luxurious, and technologically advanced vehicles.

W140 Generation:

The W140 generation (1991-1998) was a significant redesign, known for its size, technology, and build quality, but also for its higher development costs and initial complexity.

Production Years:

W140 series produced from 1991 to 1998. The S320 specifically was a core model within this range.

🏆 Awards & Recognition

Industry Acclaim:

The W140 chassis, including the S320, was recognized for its engineering, safety, and luxury, often setting benchmarks for the segment.

Reliability:

While considered robust, the complexity and age of W140 models mean that regular maintenance and proactive repairs are crucial for optimal reliability. Initial reliability ratings were generally good, but maintenance sensitivity is high.