🏷️ Basic Information

Make:

Mercedes-Benz

Model:

124 Coupe

Model Variant:

300CE

Engine Variant:

3.0L Inline-6

Year Range:

1988-1992

Chassis Code:

C124

Engine Code:

M103.980

👋 Introduction

Positioning:

The Mercedes-Benz 124 Coupe, particularly the 300CE, represented a pinnacle of luxury, engineering, and build quality in the late 1980s and early 1990s. Positioned as a grand tourer with coupe styling, it appealed to discerning buyers seeking refinement, performance, and the enduring prestige of the Mercedes-Benz brand.

Competitors:

Competed with other premium coupes of its era, such as the BMW 6 Series (E24 generation successor), Audi Coupe, and American luxury coupes from Cadillac and Lincoln, though often with a stronger emphasis on sophisticated engineering and build solidity.

Features:

Robust build quality, refined ride comfort, powerful yet smooth inline-six engine, advanced (for its time) safety features, elegant coupe styling, and the characteristic Mercedes-Benz engineering excellence.

Value:

This digital service manual provides essential, in-depth technical information for maintaining and repairing the Mercedes-Benz 124 Coupe 300CE. It empowers owners and technicians with the knowledge to perform tasks accurately, ensuring the longevity and optimal performance of this classic Mercedes-Benz model.

📋 Manual Details

Systems Covered:

Engine Mechanical, Fuel System, Ignition System, Cooling System, Exhaust System, Clutch, Manual Transmission, Automatic Transmission, Driveshaft, Differential, Suspension (Front & Rear), Steering, Brakes (Front & Rear), Electrical System, Body & Chassis, Interior Trim, Climate Control, Wiring Diagrams.

Estimated Pages:

Approx. 1000+ pages (typical for comprehensive Mercedes-Benz service manuals of this era)

Type:

Factory Service Manual / Workshop Manual

Language:

English

Format:

Digital PDF (Instant Download)

📖 Manual Coverage

Engine Mechanical:

Detailed engine overhaul procedures, cylinder head removal and installation, piston and connecting rod service, crankshaft and bearing service, camshaft and valve train maintenance, timing chain replacement, lubrication system, oil pump service.

Fuel System:

Bosch KE-Jetronic fuel injection system diagnosis and repair, fuel pump, fuel injectors, airflow meter, cold start valve, idle speed control, fuel pressure regulator, fuel tank and lines.

Ignition System:

Distributor, ignition coil, spark plugs, ignition module, ignition timing adjustment, troubleshooting ignition faults.

Cooling System:

Radiator, water pump, thermostat, coolant hoses, fan clutch, heater core, troubleshooting overheating and leaks.

Transmission:

4-speed automatic transmission (722.3 series) service, including torque converter, valve body, transmission fluid flush and replacement, shift linkage adjustment, troubleshooting transmission performance.

Suspension Steering:

Front and rear suspension component inspection and replacement (struts, springs, control arms, bushings), steering gear service, power steering system diagnosis, wheel alignment specifications.

Brakes:

Front and rear disc brake service (pads, rotors, calipers), hydraulic system, ABS (Anti-lock Braking System) components and diagnosis, brake fluid specifications and bleeding procedures.

Electrical System:

Comprehensive wiring diagrams, battery service, starter motor, alternator, lighting system, instrument cluster, power windows, power seats, central locking, fuse box layout, troubleshooting electrical faults.

Maintenance:

Scheduled maintenance tasks, oil and filter changes, air filter replacement, spark plug replacement, fluid level checks and top-ups, brake pad inspection, belt checks.

Troubleshooting:

Diagnostic procedures for common and uncommon issues across all vehicle systems, fault code interpretation (where applicable), systematic troubleshooting guides.

Repair Rebuild:

Detailed step-by-step instructions for component removal, disassembly, inspection, repair, reassembly, and installation for major vehicle systems.

Depth:

Comprehensive, covering everything from basic routine maintenance to complex engine and transmission overhauls, electrical system diagnostics, and bodywork repair. Suitable for professional technicians and skilled DIY enthusiasts.

📊 Manual Specifications

Format:

PDF

Searchability:

Searchable text content for quick information retrieval.

Quality:

High-resolution scans with clear text and legible diagrams/illustrations.

Type:

Not Applicable (Digital Download)

Type:

Not Applicable (Digital Download)

⚙️ Engine Specifications

Engine Type:

Naturally Aspirated Inline-6 (M103)

Displacement:

2960 cc (3.0 Liters)

Horsepower:

Approx. 180-188 hp (varies slightly by market and year)

Torque:

Approx. 240-250 Nm (177-184 lb-ft)

Injection System:

Bosch KE-Jetronic Electronic Fuel Injection with Pneumatic Control

Fuel Requirement:

Unleaded Gasoline (Octane rating typically 91 RON or higher)

Coolant Type:

Proprietary Mercedes-Benz coolants or equivalent (e.g., Glysantin G05 or similar).

Oil Capacity With Filter:

Approx. 7.5 Liters (7.9 US Quarts)

Recommended Oil Viscosity:

SAE 10W-40 or 15W-50 (depending on climate conditions)

Spark Plugs:

Typically Bosch W8DP or equivalent

🔧 Transmission

Type:

4-Speed Automatic (722.3 series)

Type:

5-Speed Manual (G5-20, rare for 300CE but available on other 124 models)

Automatic Features:

Hydraulic torque converter, electronic control unit (ECT) for shift points, lockout converter (torque converter clutch) for improved fuel economy at cruising speeds.

Automatic Transmission Fluid:

Mercedes-Benz Automatic Transmission Fluid (ATF) - typically Dexron II or equivalent.

Automatic Transmission Fluid Capacity:

Approx. 8.0 Liters (dry fill), 7.0 Liters (fluid change)

📐 Dimensions

Length:

Approx. 4735 mm (186.4 in)

Width:

Approx. 1740 mm (68.5 in)

Height:

Approx. 1380 mm (54.3 in)

Wheelbase:

Approx. 2715 mm (106.9 in)

Curb Weight:

Approx. 1560 kg (3439 lbs)

Gross Vehicle Weight Rating:

Approx. 2040 kg (4500 lbs)

🛡️ Safety Features

Crash Test Results:

While official independent crash test ratings from bodies like NHTSA or IIHS for this specific early model are scarce, the W124 platform was renowned for its robust safety cage, energy-absorbing crumple zones, and strong overall structural integrity, considered excellent for its era.

ABS:

Standard Anti-lock Braking System (ABS) on later models and often as an option on earlier ones.

Traction Control:

Optional ASR (Acceleration Slip Regulation) available on some later models within this range.

Airbags:

Driver's side airbag typically standard from the late 1980s onwards. Passenger airbag and seatbelt pretensioners were also available or standard on later versions.

Seatbelts:

Height-adjustable front seat belts with pretensioners, rear seat belts.

Body Structure:

Reinforced passenger compartment, side-impact protection beams, energy-absorbing steering column.

💡 Technology Features

Audio System:

Factory premium sound systems with cassette player. Often equipped with Becker radios. Manual details electrical connections and speaker replacements.

Climate Control:

Manual or automatic climate control systems. Manual covers operation, troubleshooting, and component replacement (compressor, blower motor, climate control unit).

Cruise Control:

Standard cruise control system. Manual covers diagnosis and repair of the vacuum or electronic control unit.

Central Locking:

Vacuum-operated central locking system. Manual details the system's operation, vacuum pump, and actuator troubleshooting.

Antennas:

Power antenna system, often integrated into the windshield or rear glass on later models. Manual covers electrical and mechanical repair.

🔧 Maintenance

Oil Filter Change:

Every 7,500 - 10,000 miles (12,000 - 16,000 km) or annually, whichever comes first.

Air Filter Replacement:

Every 15,000 - 20,000 miles (24,000 - 32,000 km) or as needed based on driving conditions.

Spark Plug Replacement:

Every 30,000 - 40,000 miles (48,000 - 64,000 km) for standard plugs.

Transmission Fluid Change:

Every 30,000 - 50,000 miles (48,000 - 80,000 km) for automatic transmissions, including filter replacement.

Coolant Flush:

Every 2-3 years or 30,000 - 50,000 miles (48,000 - 80,000 km).

Brake Fluid:

DOT 4 (Mercedes-Benz specification)

Power Steering Fluid:

Mercedes-Benz Power Steering Fluid or Pentosin CHF 11S.

Wiring Harness:

Degradation of the under-hood wiring harness insulation ('crackle-free' wiring issue, typically affects later models but can occur). Manual will detail inspection and repair procedures.

Fuel Delivery:

Weak fuel pumps or failing fuel pressure regulators are common issues affecting the KE-Jetronic system. Manual covers diagnosis and replacement.

Vacuum Lines:

Cracked or leaking vacuum lines can cause idle issues and performance problems. The manual provides diagrams and troubleshooting steps.

Headliner:

Sagging headliner fabric is a common cosmetic issue due to adhesive failure. Manual may cover headliner removal/replacement.

Rust Prone Areas:

Check wheel wells, rocker panels, door bottoms, and trunk lid for corrosion. Manual may offer body repair guidance.

📚 Vehicle History

Heritage:

Mercedes-Benz has a long-standing reputation for automotive engineering excellence, safety, and luxury, dating back to its origins in the late 19th century. The W124 generation (1984-1995) is often considered one of the most over-engineered and durable Mercedes-Benz models ever produced.

W124 Development:

The W124 chassis was developed as a successor to the W123 series. It was introduced in 1984 as a sedan, followed by the Estate (T-model), Coupe (C124), and Convertible (A124) variants. The Coupe, launched in 1987, offered a sportier and more elegant interpretation of the W124's renowned engineering.

300Ce Introduction:

The 300CE, featuring the 3.0L M103 engine, was introduced to offer a balance of performance and refinement, slotting below the more powerful 300CE-24V and 500CE models that would emerge later in the W124 lifecycle.

Production Period:

The C124 Coupe was produced from 1987 to 1996. The 300CE variant specifically covered the earlier years of this range (1988-1992), before being replaced by the E320 Coupe.

Manufacturing Location:

Mainly manufactured in Germany.

🏆 Awards & Recognition

Build Quality Reputation:

The W124 platform, including the 300CE, consistently received praise from automotive journalists and owners for its exceptional build quality, durability, and long-term reliability. Often cited as a benchmark for luxury car manufacturing in its era.

Automotive Journalism Acclaim:

Frequently lauded for its sophisticated engineering, comfortable ride, and confident handling, solidifying Mercedes-Benz's reputation for producing premium grand tourers.