🏷️ Basic Information

Make:

Mercedes-Benz

Model:

300 TD Turbo

Model Code:

W123 Series (specific chassis codes apply, e.g., 123.130)

Year:

1981-1985

Engine Code:

OM617.952 (inline 5-cylinder turbo-diesel)

👋 Introduction

Market Position:

The Mercedes-Benz 300 TD Turbo (W123) represented the pinnacle of diesel luxury and durability in its era, known for its robust engineering and exceptional longevity. This manual serves the owners and mechanics dedicated to preserving and maintaining these iconic vehicles.

Competitive Analysis:

Competed against other premium diesel sedans and wagons, but was often distinguished by its build quality, advanced (for the time) diesel technology, and the prestige associated with the Mercedes-Benz brand. Its reliability set it apart.

Key Features:

Turbocharged diesel engine for improved performance, spacious and luxurious interior, excellent ride comfort, legendary Mercedes-Benz build quality and durability. This manual unlocks the secrets to maintaining these characteristics.

📋 Manual Details

Coverage Areas:

All aspects of repair, maintenance, diagnostics, and rebuilding for Mercedes-Benz 300 TD Turbo (W123 chassis) models from 1981 to 1985.

Page Count:

Extensive (typically over 1000 pages for a comprehensive service manual of this era, though exact count not specified in product info)

Manual Type:

Service and Repair Manual

Language:

English

Format:

Likely printed manual or high-quality PDF

📖 Manual Coverage

Systems Covered:

Engine Mechanical, Engine Electrical, Fuel System (including injection pump and injectors), Turbocharging System, Cooling System, Lubrication System, Exhaust System, Clutch, Manual Transmission, Automatic Transmission (if applicable for model year/market), Driveshaft, Differential, Suspension (Front and Rear), Steering System, Brakes (Hydraulic and Parking), Electrical System (wiring diagrams, components), Lighting, Body Panels and Trim, Interior Components, Climate Control, Diagnostic Procedures, Troubleshooting.

Procedures Included:

Routine Maintenance (oil changes, filter replacements, tune-ups), Component Removal and Installation, Engine Overhaul and Rebuilding, Transmission Service and Repair, Brake System Overhaul, Suspension Component Replacement, Steering System Adjustments, Electrical Troubleshooting and Repair, Bodywork and Dent Repair, Climate Control System Servicing, Diagnostic Codes and Interpretation, Torque Specifications, Component Specifications, Wiring Diagrams, Special Tool Requirements.

Technical Depth:

Comprehensive, covering everything from basic preventive maintenance to complete engine and transmission rebuilds, including detailed diagnostic strategies and step-by-step repair instructions. Suitable for professional technicians and advanced DIY enthusiasts.

📊 Manual Specifications

File Format:

If PDF: Searchable text, high-resolution images and diagrams, printable pages. If Print: Durable binding, clear ink, high-quality paper.

Print Quality:

Professional quality, clear diagrams and text for ease of use in a workshop environment.

Binding Type:

If Print: Likely spiral-bound or sturdy paperback for workshop durability.

Paper Type:

If Print: Heavy-duty paper stock to withstand grease and workshop conditions.

⚙️ Engine Specifications

Primary Engine:

3.0L (2998cc) OM617.952 Inline 5-Cylinder Turbocharged Diesel

Horsepower:

Approximately 125 hp @ 4350 rpm

Torque:

Approximately 180 lb-ft (244 Nm) @ 2400 rpm

Fuel System:

Bosch inline mechanical fuel injection pump (e.g., PES 6 ME 70 B 320 RS) with pre-heating glow plugs.

Engine Construction:

Cast iron block, aluminum alloy cylinder head.

Bore Stroke:

91.0 mm x 115.0 mm

Compression Ratio:

21.0:1

🔧 Transmission

Standard Transmission:

4-speed Manual Transmission (often denoted as 717.400 series)

Optional Transmission:

4-speed Automatic Transmission (e.g., 722.3 series)

Transmission Features:

Robust and durable transmissions known for their longevity. Automatic versions feature hydraulic torque converter.

📐 Dimensions

Wheelbase:

Approx. 110.2 inches (2799 mm)

Length:

Approx. 188.2 inches (4780 mm)

Width:

Approx. 69.7 inches (1770 mm)

Height:

Approx. 56.1 inches (1425 mm)

Curb Weight:

Approx. 3500 - 3700 lbs (1588 - 1678 kg), depending on body style and equipment.

🛡️ Safety Features

Safety Ratings:

As a vehicle from the early 1980s, official crash test ratings (like NHTSA or IIHS) in the modern sense were not as prevalent or standardized. However, Mercedes-Benz vehicles of this era were engineered with a strong emphasis on passive safety.

Active Features:

Four-wheel disc brakes (ventilated front), power steering, sophisticated independent suspension for stable handling.

Passive Features:

Reinforced passenger safety cell, crumple zones, padded interior surfaces, impact-absorbing steering column, dual-circuit braking system, seat belts (three-point in front).

💡 Technology Features

Infotainment:

Basic analog radio, cassette player (optional), analog gauges for speed, RPM, fuel, temperature, oil pressure. Focus is on mechanical reliability over electronic features.

Driver Assistance:

Cruise control (vacuum operated), power windows, power locks (vacuum operated), power antenna (optional). No modern electronic driver assistance systems.

Connectivity:

None in the modern sense. Primarily analog electrical systems.

🔧 Maintenance

Service Intervals:

Oil Change: Every 5,000 miles (8,000 km) or 6 months. Fuel Filter: Every 15,000 miles (24,000 km). Air Filter: Every 15,000 miles (24,000 km) or as needed. Coolant Flush: Every 2 years or 30,000 miles (48,000 km). Valve Adjustment: Recommended at higher mileage intervals or if tappet noise is present. Transmission Fluid: Check regularly, change based on severe service (e.g., every 30,000 miles for automatic).

Engine Oil Spec:

API CD or higher, SAE 15W-40 or 10W-40 diesel engine oil. Capacity: Approx. 7.5 liters (8 quarts) with filter.

Coolant Spec:

Mercedes-Benz approved antifreeze/coolant (typically a silicate-free, long-life coolant). Mix 50/50 with distilled water. Capacity: Approx. 10 liters.

Transmission Fluid Automatic:

MB Approval 236.1 (e.g., Dexron III/Mercon compatible, but check manual for exact specification). Capacity: Approx. 7-9 liters for torque converter change.

Brake Fluid Spec:

DOT 3 or DOT 4 (check manual for specific recommendation). Capacity: Approx. 1 liter.

Known Issues:

Cracking of dashboard (alligatoring), vacuum system leaks affecting door locks and cruise control, front suspension ball joint wear, potential for oil cooler seal leaks, injector pump timing sensitivity, early model rust issues (especially in certain climates), turbocharger maintenance. The manual provides solutions for these common concerns.

Fuel Filter Part Number:

Examples: Mann-Filter WK 80, Mahle KL 12

Oil Filter Part Number:

Examples: Mann-Filter HU 718/1x, Mahle OC 203

📚 Vehicle History

Brand Heritage:

Mercedes-Benz has a long-standing reputation for engineering excellence, safety, and luxury, dating back to the invention of the automobile itself. This heritage is reflected in the robust construction of the W123.

Model Evolution:

The W123 chassis, introduced in 1976, replaced the W114/W115 series. The 300 TD Turbo variant, introduced later in the W123's lifecycle (around 1982 for North America), offered a significant performance boost over its naturally aspirated predecessors through the integration of a turbocharger. It was available as a sedan, coupe, and wagon (T-model).

Production Years:

W123 series produced from 1976 to 1986. The 300 TD Turbo variants specifically fall within the latter half of this production run, 1981-1985 being the core years covered by this manual.

🏆 Awards & Recognition

Recognitions:

The W123 chassis as a whole is widely recognized for its 'built like a tank' reputation and exceptional durability, often cited as one of the most reliable Mercedes-Benz models ever produced. Specific awards for the 300 TD Turbo are less common than the overall model's esteemed legacy.