🏷️ Basic Information

Make:

Mercedes-Benz

Model:

E-Class

Chassis Code:

W124

Model Year:

1991

👋 Introduction

Positioning:

The Mercedes-Benz W124 represented the pinnacle of German engineering and build quality for its era, often referred to as the 'last of the over-engineered' Mercedes. It competed against other premium sedans and coupes from brands like BMW, Audi, and Lexus.

Manual Benefits:

This manual provides exact, vehicle-specific information identical to what dealership technicians use, enabling DIY owners to accurately maintain, diagnose, and repair their W124 with confidence and efficiency.

Digital Advantage:

The PDF format offers convenience, searchability, and the ability to print only necessary pages, preventing wear and tear on a physical manual and providing on-the-spot access at the vehicle or workshop.

📋 Manual Details

Primary Coverage:

All 1991 Mercedes-Benz W124 E-Class models and all repairs A-Z

Estimated Page Count:

Likely extensive, typical for factory-level repair manuals (e.g., 800-1500+ pages when printed)

Type:

Factory Service and Repair Manual (Digital Format)

Language:

English

Digital Format:

PDF

📖 Manual Coverage

Engine:

Comprehensive coverage including maintenance, diagnosis, and repair of gasoline and diesel engines

Fuel System:

Fuel delivery, injection systems (KE-Jetronic, etc.), fuel pumps, injectors, and specifications

Emission Control:

Catalytic converters, oxygen sensors, EGR systems, emission testing procedures

Cooling System:

Radiator, coolant, water pump, thermostat, cooling fan operation and repair

Lubrication System:

Oil pump, oil filter, oil pressure, lubrication intervals and specifications

Ignition Starting Charging:

Ignition system components, starting motor, alternator, battery, and wiring schematics

Automatic Transmission:

Service, diagnosis, repair, fluid specifications, and control systems for automatic transmissions

Manual Transmission:

Service and repair procedures for manual transmissions (if applicable to specific W124 models)

Drivetrain:

Driveshafts, universal joints, propeller shafts, differentials, and axle components

Suspension Steering:

Front and rear suspension components, steering systems, power steering, alignment specifications

Brakes:

Brake system components, hydraulic systems, ABS (if equipped), brake fluid specifications, service and repair

Parking Brake:

Operation and adjustment of the parking brake system

Air Conditioning:

Refrigerant, system operation, diagnosis, and repair of the climate control system

Body Exterior:

Body panels, doors, hood, trunk, glass, mirrors, exterior trim, and repair procedures

Body Interior:

Seats, upholstery, instrument panel, interior trim, and related components

Electrical System:

Comprehensive electrical system coverage, including lighting, power windows, central locking, wipers, and more

Wiring Schematics:

Detailed wiring diagrams for all electrical systems and components

Supplemental Restraint System:

Airbag systems (SRS) and seat belt pre-tensioners (if equipped)

Cruise Control:

Operation, diagnosis, and repair of the cruise control system

Engine Immobilizer:

Information on the engine immobilizer system (if applicable)

Multiplex Communication:

Information on multiplex or CAN communication systems (may be basic for this era)

Maintenance:

Routine maintenance schedules, fluid checks, filter replacements, inspections

Troubleshooting:

Diagnostic procedures, symptom-based troubleshooting guides, fault code interpretation (if applicable)

Repair:

Detailed step-by-step repair instructions for all major and minor components

Disassembly Reassembly:

Complete instructions for disassembling and reassembling all vehicle systems

Technical Specifications:

Torque values, clearances, fluid capacities, pressure specifications

Diagrams Illustrations:

Abundant diagrams, illustrations, and exploded views to aid in understanding and repair

Depth:

Factory-level detail, covering basic maintenance to complete engine and transmission rebuilds, advanced diagnostics, and electrical system troubleshooting

📊 Manual Specifications

Format:

PDF (Adobe Acrobat Reader required)

Printability:

All pages are printable, allowing for enlarged viewing of diagrams and specific sections

Binding:

Not applicable (digital format)

Paper Type:

Not applicable (digital format, users print on demand)

Operating Systems:

Windows Vista (32/64), XP, ME, 98, NT, 2000, and Mac compatible

Software Requirements:

Adobe PDF Reader and Winzip (or similar unzipping utility) required, both available for free online

⚙️ Engine Specifications

Engine Options 1991:

Likely includes gasoline engines such as the M102 (2.0L, 2.3L, 2.6L) and M103 (3.0L, 3.2L), and diesel engines like the OM601 (2.0L Diesel), OM602 (2.5L Diesel, 2.9L Diesel), and OM603 (3.0L Diesel). Specific engine codes for the 1991 model year should be confirmed for precise identification.

Horsepower Torque Range:

Varies significantly by engine, generally ranging from approximately 70-90 hp for naturally aspirated diesels to 130-180 hp for gasoline engines. Torque figures also vary accordingly.

Fuel Injection Type:

Primarily Bosch KE-Jetronic (mechanical-electronic fuel injection) for gasoline engines, with electronic fuel injection becoming more prevalent in later W124 iterations. Diesel engines utilize mechanical injection pumps.

Engine Oil Type:

Consult manual for specific viscosity (e.g., 10W-40, 15W-40, or synthetic equivalents like 5W-40/0W-40 depending on climate and engine type). API service classification is critical. Mercedes-Benz specifications (e.g., MB 228.1, MB 229.1) are often recommended.

🔧 Transmission

Transmission Options:

Typically offered with a 4-speed automatic transmission (e.g., 722.4) as standard on many models. A 5-speed manual transmission was also available on some variants.

Transmission Options:

5-speed automatic transmission (722.5 with overdrive lock-up clutch) was optional on some higher-spec models.

Automatic Transmission Features:

Features like 'Economy' and 'Sport' modes were common on automatic transmissions of this era.

Automatic Transmission Fluid:

Typically requires Dexron II or equivalent ATF. MB specification 236.1 is crucial. Consult manual for precise fluid type and capacity.

📐 Dimensions

Body Styles:

Available as a 4-door sedan (Saloon), 5-door wagon (Estate/Kombi), 2-door coupe, and 2-door convertible (A124).

Curb Weight:

Varies significantly by body style and engine. Typically ranges from approximately 3,000 lbs (1360 kg) for sedans to over 3,700 lbs (1680 kg) for wagons and coupes.

🛡️ Safety Features

Crash Safety:

While official crash test ratings (like NHTSA or Euro NCAP) were less standardized in 1991, the W124 was renowned for its robust safety cage, crumple zones, and strong structural integrity, earning a reputation for exceptional passive safety.

ABS:

Anti-lock Braking System (ABS) was available as an option on many W124 models and standard on some higher-spec variants.

Airbags:

Driver's side airbag became optional and later standard on many W124 models by the early 1990s. Passenger airbags were not common for this model year.

Seatbelts:

Features pre-tensioners on front seat belts on some models.

💡 Technology Features

Audio Visual:

Factory stereo systems were typically AM/FM cassette players, often with premium speaker options. CD changers were available as an aftermarket or dealer option. The manual will cover basic operation and troubleshooting of these systems.

Cruise Control:

Standard cruise control system, often vacuum-actuated or electronically controlled depending on the exact model and options.

OBD Ii:

The W124 pre-dates the OBD-II standard. Diagnostic capabilities would typically involve proprietary Mercedes-Benz diagnostic tools and procedures, which would be detailed in this manual.

🔧 Maintenance

Oil Change Interval:

Typically every 5,000 to 7,500 miles (8,000 to 12,000 km) or annually, depending on driving conditions and oil used. Diesel engines might have slightly longer intervals. Consult manual for precise recommendations.

Transmission Fluid Change:

Often recommended every 30,000 to 50,000 miles (48,000 to 80,000 km) for automatic transmissions. Manual transmissions may have longer intervals or be considered sealed for life, though periodic checks are advised.

Coolant Type:

Ethylene glycol-based antifreeze. Mercedes-Benz approved coolant (e.g., G48) is recommended. Mix ratio typically 50/50 with distilled water.

Brake Fluid Type:

DOT 3 or DOT 4 brake fluid. Regular flushing and replacement (typically every 2 years) is critical for system performance and longevity.

Common W124 Problems:

Potential issues include wiring harness degradation (especially insulation breakdown), fuel distributor leaks (on KE-Jetronic), vacuum hose deterioration, rust in common areas (wheel wells, sills), and occasional electronic control module failures. Early warning indicators are crucial.

Oil Filter Part Number:

Part numbers vary by engine. For example, a common filter for some M102/M103 engines might be a Mann-Filter W914/2 or equivalent Bosch 0451103201. Always verify with the manual for your specific engine.

📚 Vehicle History

Mercedes Benz Legacy:

Mercedes-Benz has a long history of producing robust, reliable, and technologically advanced luxury vehicles. The W124 lineage continued this tradition with exceptional build quality and durability.

W124 Development:

The W124 replaced the W123 and was produced from 1984 to 1995 (with facelifted versions appearing in 1989 and 1993). It was lauded for its aerodynamic design, multi-link rear suspension, and excellent ride comfort.

Production Period:

1984-1995. The 1991 model year falls within the facelifted phase of the W124, featuring updated styling and some mechanical enhancements.

🏆 Awards & Recognition

Model Reputation:

The W124 series is widely regarded as one of the most durable and well-built Mercedes-Benz models ever produced. It consistently received praise for its engineering, comfort, and longevity in automotive journalism.