🏷️ Basic Information

Make:

Mercedes-Benz

Model:

300 D

Engine Variant:

2.5 Turbo Diesel

Model Code:

W124 E300 TD

Chassis Code:

W124

👋 Introduction

Segment:

Mid-size Luxury Sedan / Estate (Wagon)

Target Audience:

Discerning owners valuing comfort, durability, and engineering over outright performance.

Key Competitors:

BMW 5 Series (E34), Audi 100 (C3/C4), Volvo 240/740 (less premium but similar market segment).

Brand Reputation:

Mercedes-Benz known for build quality, safety, and longevity.

Model Strengths:

Robust diesel engine, excellent ride comfort, durable construction, sophisticated design for its era.

📋 Manual Details

Major Systems:

Engine, Drivetrain, Suspension, Steering, Brakes, Electrical System, HVAC, Body, Fuel System, Exhaust System, Cooling System

Specific Components:

Turbocharger, Diesel Injection Pump (Bosch VE), Glow Plugs, Pre-Glow Timer, Automatic Climate Control, ABS (Anti-lock Braking System), SRS (Supplemental Restraint System), Power Steering System, Differential, Driveshafts, Radiator, Fan Clutch, Water Pump, Diesel Particulate Filter (if applicable to specific market/year)

Estimated Pages:

800-1200 (typical for comprehensive workshop manuals of this era)

Type:

Service and Repair Manual

Primary Language:

English

Digital Format:

PDF

📖 Manual Coverage

Engine Mechanical:

Detailed overhaul procedures for the OM602.912 engine, including cylinder head, piston, crankshaft, camshaft, valve train, timing chain, and oil pump replacement.

Engine Fuel System:

Diagnosis and repair of the Bosch VE injection pump, injectors, fuel lines, fuel filter, and pre-heating system.

Engine Cooling System:

Service and repair of the radiator, coolant hoses, thermostat, water pump, and fan clutch.

Engine Lubrication System:

Oil filter replacement, oil change intervals, oil pump service, and oil pan repair.

Engine Turbocharger:

Diagnosis, removal, installation, and inspection of the turbocharger unit.

Transmission:

Service and repair of the automatic transmission (e.g., 722.4), including fluid changes, filter replacement, and valve body diagnosis.

Drivetrain:

Front and rear axle service, driveshaft inspection, universal joint replacement, and differential service.

Suspension:

Front and rear suspension component replacement (struts, control arms, ball joints, bushings), wheel alignment procedures.

Steering:

Power steering system diagnosis and repair, steering column service, tie rod end replacement.

Brakes:

Front and rear brake pad and rotor replacement, brake caliper service, brake fluid flush and bleeding, ABS system diagnosis.

Electrical System:

Wiring diagrams, fuse box layouts, starter, alternator, battery service, lighting system repair, SRS system diagnosis and component replacement.

HVAC:

Air conditioning system service, heater core replacement, climate control unit diagnosis.

Bodywork:

Door panel removal, exterior trim, glass replacement, body panel repair basics.

Routine Maintenance:

Oil and filter changes, air filter replacement, fuel filter replacement, coolant flush, spark plug replacement (if applicable to gas models, but not this diesel), brake fluid replacement, power steering fluid replacement.

Troubleshooting:

Diagnostic flowcharts and procedures for common drivability issues, electrical faults, and mechanical problems.

Repair Rebuild:

Step-by-step instructions for component removal, installation, overhaul, and rebuilding of major vehicle systems.

Diagnostics:

Specific diagnostic procedures for engine management, ABS, SRS, and other electronic systems, including fault code retrieval if applicable.

Adjustments:

Valve lash adjustment (if applicable to diesel), idle speed adjustment, timing adjustments.

Torque Specifications:

Detailed torque values for all critical fasteners during assembly and disassembly.

Depth Level:

Comprehensive: Covers everything from basic maintenance to complete engine and transmission overhauls, including in-depth electrical troubleshooting.

📊 Manual Specifications

File Type:

Searchable PDF

Searchability:

Full text searchable for quick access to information.

Image Resolution:

High-resolution scans of original diagrams and photographs.

Digital Access:

Instant download

Digital Quality:

Optimized for digital viewing and printing.

⚙️ Engine Specifications

Engine Code:

OM602.912

Engine Type:

Inline 5-cylinder, turbocharged, direct injection diesel

Displacement:

2.5 Liters (2497 cc)

Horsepower:

126 hp (94 kW) at 4600 rpm

Torque:

181 lb-ft (245 Nm) at 2400 rpm

Injection System:

Bosch VE (Distributor Type) Rotary Injection Pump

Fuel Type:

Diesel Fuel

Coolant Type:

Glysantin G05 or equivalent (Blue/Green)

Oil Capacity With Filter:

7.5 Liters (7.9 US Quarts)

Recommended Oil Viscosity:

SAE 15W-40 (API CD or higher)

🔧 Transmission

Type:

4-speed Automatic Transmission (722.4)

Type:

5-speed Manual Transmission

Automatic Features:

Lock-up torque converter, electronic control (later models may have more advanced control).

Automatic Transmission Fluid:

MB 236.2 or MB 236.6 ATF (e.g., Dexron II)

Capacity:

Approx. 6.5 Liters (6.9 US Quarts) for a complete fill.

📐 Dimensions

Length:

Approx. 4740 mm (186.6 in) for Sedan, 4970 mm (195.7 in) for Wagon

Width:

Approx. 1740 mm (68.5 in)

Height:

Approx. 1430 mm (56.3 in) for Sedan, 1460 mm (57.5 in) for Wagon

Curb Weight:

Approx. 1550 kg (3417 lbs) for Sedan

Bolt Pattern:

5x112

Center Bore:

66.5 mm

Lug Nut Size:

M14x1.5

Standard Fitment:

205/60R15 (check specific model/trim)

🛡️ Safety Features

Era Specific Ratings:

While formal NHTSA/Euro NCAP ratings in the modern sense were less standardized, the W124 platform was renowned for its robust safety cell and crashworthiness for its time.

ABS:

Standard on most models within this year range (Bosch ABS).

Airbags:

Driver's airbag became standard in later years of this generation. Passenger airbag was optional.

Seatbelts:

Front seatbelt pretensioners, rear seatbelt anchorages.

Rollover Protection:

Reinforced A and B pillars, strong roof structure.

💡 Technology Features

Radio:

Original units typically cassette players with AM/FM radio. Some later models may have had CD changers as an option.

Speakers:

Typically 4-6 speakers, depending on trim level.

Cruise Control:

Standard or optional on most models.

Traction Control:

ASR (Acceleration Slip Regulation) was optional on some models, not universally standard.

System Type:

Manual or automatic climate control (THERMATIC/THERMATIC Luxe). Recirculation mode, pollen filter (location varies).

🔧 Maintenance

Oil And Filter Change:

Every 10,000 - 15,000 km (6,000 - 9,000 miles) or 12 months, whichever comes first.

Fuel Filter Replacement:

Every 30,000 - 45,000 km (18,000 - 27,000 miles).

Air Filter Replacement:

Every 30,000 - 45,000 km (18,000 - 27,000 miles).

Coolant Flush And Replacement:

Every 2-3 years or 50,000 km (30,000 miles).

Transmission Fluid And Filter Change:

Every 60,000 - 80,000 km (36,000 - 50,000 miles) for automatic transmissions.

Brake Fluid:

DOT 3 or DOT 4 (MB approved)

Power Steering Fluid:

MB Spec 236.3 (e.g., Pentosin CHF 11 S is often used as a substitute, confirm compatibility)

Coolant Antifreeze Mixture:

50/50 mix of approved antifreeze and distilled water.

Diesel Specific:

Glow plug failure, injection pump seals, diesel injector issues, vacuum line degradation.

Common W124:

Heated wiper parking switch failure, headliner sagging, rust (especially around wheel wells and rear quarters), vacuum leaks affecting central locking/door locks, biodegradable wiring insulation breakdown (in some earlier models, less common for this specific year range but worth noting), odometer gear failure.

Engine Filters:

Fuel Filter: Mann-Filter WK80, Mahle KL114, Bosch 0450905308 (confirm via part number cross-reference).

📚 Vehicle History

Parent Company:

Daimler-Benz AG (now Mercedes-Benz Group AG)

W124 Introduction:

The W124 chassis was introduced in 1984, renowned for its over-engineered build quality and durability. The diesel variants, particularly the turbocharged ones, cemented Mercedes-Benz's reputation for robust powertrains.

300 D Introduction:

The 300 D 2.5 Turbo was part of the W124's facelifted range and represented a significant upgrade in power and refinement for Mercedes diesel sedans of the era.

Production Years:

1990-1993 (for the specific 300 D 2.5 Turbo variant)

Manufacturing Plants:

Primarily Sindelfingen, Germany; also some production in other global facilities.

🏆 Awards & Recognition

Model Accolades:

The W124 platform consistently received accolades for its build quality, durability, and refinement, often cited as one of the best-engineered Mercedes-Benz models ever produced.

Consumer Reports:

Highly rated for reliability and durability by automotive publications of the era.

Engineering Standards:

Built to exceed DIN and ISO automotive engineering standards common in Germany.