🏷️ Basic Information

Make:

Mercedes-Benz

Model:

W123

Engine Code:

OM617.95 Turbo Diesel

Body Style:

Sedan, Coupe, Wagon, Limousine (covered by model series, specific body style details not explicitly detailed in product info)

Generation:

First Generation (1976-1985)

Chassis Code:

W123

👋 Introduction

Market Position:

A comprehensive technical resource catering to owners and mechanics of the Mercedes-Benz W123 series equipped with the OM617.95 Turbo Diesel engine, offering dealership-level repair and maintenance information for a classic luxury vehicle.

Competitive Analysis:

This manual provides official factory repair data, distinguishing it from generic repair guides. Its focus on the specific OM617.95 turbo diesel engine and the W123 chassis offers a level of detail and accuracy crucial for servicing this particular model, making it indispensable for enthusiasts and professionals alike.

Key Features:

Official factory information, comprehensive coverage of all major vehicle systems, detailed troubleshooting guides, high-quality printable PDF format, instant download accessibility, specific focus on the OM617.95 Turbo Diesel engine.

📋 Manual Details

Coverage Areas:

General Maintenance, Troubleshooting, Engine Service/Repair, Transmission Service/Repair, Brake System, Wiring Diagram, Electrical System, Suspension, Periodic Lubrication, Steering, Cooling System, Fuel Injection, Fuel System, Emission System, Heater/Air Conditioning, Engine Control System, Chassis/Body, Restraint System, Interior, Differential/Drive, Axle, and much more.

Page Count:

Hundreds or thousands of pages (printable at great quality)

Manual Type:

Official Full Complete Factory Service Repair Manual

Language:

English

Format:

PDF

📖 Manual Coverage

Systems Covered:

Engine (OM617.95 Turbo Diesel), Drivetrain (Transmission, Differential/Drive, Axle), Braking System, Electrical System (including Wiring Diagrams), Fuel System (including Fuel Injection), Cooling System, Lubrication System, Steering System, Suspension System, HVAC System (Heater/Air Conditioning), Emission Control System, Chassis, Body, Restraint System (Airbags, Seatbelts), Interior Components.

Cooling System Details:

Radiator, fan (mechanical), water pump, thermostat, hoses, coolant passages, heater core, and climate control linkage.

Fuel Injection Details:

Bosch inline injection pump, injectors, fuel lines, pre-heating system, injection timing adjustments.

Electrical System Details:

Battery, starter, alternator, ignition system (for gasoline variants, but this manual focuses on diesel), lighting (headlights, taillights, interior), dashboard instrumentation, fuses, relays, wiring harnesses, diagnostic connectors (if applicable for the era).

Procedures Included:

General maintenance tasks, diagnostic procedures for troubleshooting, detailed engine repair and overhaul, transmission service and repair, brake system inspection and repair, electrical system diagnosis and repair, suspension and steering alignment and repair, cooling system maintenance, fuel system and injection system servicing, emission control system adjustments, HVAC system servicing, chassis and body repair, interior trim removal and installation, lubrication procedures, component replacement, and much more.

Troubleshooting Methodology:

Systematic diagnostic procedures, identifying symptoms and tracing them to potential causes, including electrical tests, pressure tests, and component checks.

Engine Rebuild Procedures:

Complete engine disassembly, cleaning, inspection, measurement of critical components (cylinder bores, pistons, crankshaft, camshaft), and reassembly with specified tolerances and torque values.

Technical Depth:

Comprehensive factory-level repair and diagnostic information, suitable for professional technicians and advanced DIY enthusiasts. Includes technical data, diagrams, schematics, specifications, and step-by-step repair instructions.

Diagnostic Charts:

Inclusion of diagnostic flowcharts and tables to aid in pinpointing mechanical and electrical faults.

📊 Manual Specifications

File Format:

PDF (requires Adobe PDF Reader)

Print Quality:

High quality, printable pages

Binding Type:

Digital Download (PDF), unzipping may be required for larger files.

Paper Type:

N/A (Digital Format)

⚙️ Engine Specifications

Primary Engine:

Mercedes-Benz OM617.95 Turbo Diesel

Engine Displacement:

3.0 Liters (2998 cc)

Horsepower Approximate:

125 hp @ 4350 rpm (Varies slightly by specific W123 model and year)

Torque Approximate:

180 lb-ft @ 2400 rpm (Varies slightly by specific W123 model and year)

Fuel System Type:

Direct Injection, Turbocharged, Bosch Inline Fuel Injection Pump

Fuel Type:

Diesel

Turbocharger Details:

Garrett or Schwitzer turbocharger (specific model may vary by production date, covered in manual).

Glow Plug System:

Pre-heating system for cold starts, critical for diesel engine operation.

Engine Block Material:

Cast Iron

Cylinder Head Material:

Aluminum Alloy

Valve Adjustment:

Hydraulic lifters with mechanical adjustment procedures specified in the manual.

Engine Oil Capacity:

Approximately 7.5 liters (8 US quarts) including filter. Refer to manual for precise capacity.

🔧 Transmission

Standard Transmission Type:

4-speed Manual Transmission (some W123 models).

Optional Transmission Type:

4-speed Automatic Transmission (commonly found in turbo diesel models).

Automatic Transmission Features:

Hydraulic torque converter, Park, Reverse, Neutral, Drive, and selector positions for specific gears (e.g., '2', '3') for winter or engine braking.

Automatic Transmission Fluid Type:

Refer to manual for specific MB fluid specification (e.g., Dexron II equivalent or MB specific fluids depending on year).

📐 Dimensions

Wheelbase Sedan:

Approx. 110.2 inches (2799 mm)

Overall Length Sedan:

Approx. 188.2 inches (4780 mm)

Curb Weight Turbo Diesel:

Approx. 3200-3400 lbs (1450-1540 kg) depending on body style and equipment.

🛡️ Safety Features

Safety Ratings:

N/A for modern crash test ratings; however, the W123 was known for its robust body structure and safety features for its era.

Active Safety Features:

Four-wheel disc brakes (front ventilated), power assisted steering.

Passive Safety Features:

Reinforced passenger cell, energy-absorbing steering column, padded dashboard, seat belts.

💡 Technology Features

Infotainment System:

Basic analog radio (AM/FM), cassette player optional. Primarily focused on functionality over features.

Driver Assistance Features:

Power steering, power brakes, cruise control (optional on some models).

Connectivity Features:

N/A (No integrated Bluetooth, USB, or mobile connectivity).

🔧 Maintenance

Oil Change Interval Diesel:

Typically every 3,000-5,000 miles or 6-12 months (refer to manual for exact interval based on driving conditions).

Fuel Filter Replacement:

Recommended every 10,000-15,000 miles or as specified by MB for the OM617 engine.

Engine Oil Specification:

API CD or better, SAE 15W-40 or 20W-50 diesel engine oil (specific viscosity depends on ambient temperature). Refer to manual for exact MB approval.

Coolant Specification:

50/50 mix of MB approved antifreeze (e.g., G05 or equivalent) and distilled water.

Brake Fluid Type:

DOT 3 or DOT 4 hydraulic brake fluid.

Power Steering Fluid Type:

ATF (Automatic Transmission Fluid) or specific MB power steering fluid (refer to manual).

Known Issues:

Vacuum leaks in the central locking and HVAC system, potential for injector pump issues if fuel quality is poor, rust in common Mercedes-Benz areas, heater control valve failure, exhaust manifold cracks (less common on turbo models but possible).

Common Preventative Maintenance:

Regularly check and replace vacuum hoses, inspect and clean battery terminals, ensure proper coolant levels and concentration, periodic inspection of exhaust system for leaks and cracks.

📚 Vehicle History

Brand Heritage:

Mercedes-Benz, renowned for its engineering excellence, durability, and luxury vehicles since its inception.

Model Evolution:

The W123 replaced the W114/W115 series and was produced from 1976 to 1985, establishing a reputation for exceptional build quality and longevity, often referred to as 'over-engineered'.

Production Years:

1976-1985

Manufacturing Locations:

Germany (Sindelfingen, Bremen), Austria, South Africa, and others.

🏆 Awards & Recognition

Recognitions:

The W123 series received widespread acclaim for its durability, reliability, and longevity, earning it a reputation as one of the most dependable Mercedes-Benz models ever produced. Often cited in automotive enthusiast communities as a benchmark for build quality.