Positioning:
The Mercedes-Benz 300E 4Matic (W124) represented the pinnacle of executive sedan engineering for its era, offering a blend of luxury, performance, and sophisticated all-wheel-drive capability. This manual caters to owners and mechanics seeking to maintain and repair these complex vehicles.
Competitors:
Competed with models like the BMW 5 Series (E34) with xDrive, Audi V8 Quattro, and top-tier offerings from Lexus and Cadillac. The 4Matic system was a key differentiator.
Distinguishing Features:
Robust W124 chassis, legendary M103 engine durability, advanced (for its time) 4Matic all-wheel-drive system, excellent build quality, and luxury appointments.
Engine:
Complete disassembly, inspection, repair, and reassembly of M103 inline-six engine (3.0L)
Engine Management:
Bosch KE-Jetronic fuel injection system, ignition system, engine control unit (ECU) diagnostics and repair
Transmission:
4-speed automatic transmission (722.4) overhaul, adjustments, and diagnostics
Drivetrain:
4Matic all-wheel-drive system (transfer case, differentials, driveshafts) inspection and repair
Suspension:
Front independent suspension (MacPherson struts), rear multi-link independent suspension, spring and damper replacement, alignment procedures
Brakes:
Front and rear disc brakes (vented front), ABS (Anti-lock Braking System) diagnostics and repair, fluid replacement
Steering:
Hydraulic power steering system, steering gear inspection and repair
Electrical System:
Complete wiring diagrams, fuse box locations and functions, lighting systems, power accessories, battery and charging system
HVAC:
Heating, ventilation, and air conditioning (HVAC) system diagnosis and repair, refrigerant handling (R12)
Body And Chassis:
Body panel removal and installation, interior trim, glass replacement, chassis lubrication
Emission Control:
Emission control components and system checks
Maintenance:
Routine maintenance (oil changes, filter replacements, spark plugs), lubrication schedules
Troubleshooting:
Systematic diagnostic procedures for common and uncommon issues, fault code interpretation
Repair:
Detailed step-by-step repair instructions for all major components and systems
Diagnostics:
On-board diagnostics (OBD) procedures, electrical system troubleshooting charts, mechanical testing methods
Adjustments:
Valve adjustments, brake adjustments, headlight aiming, transmission adjustments
Special Tools:
Identification and usage of specialized tools required for specific procedures
Depth:
Comprehensive, factory-level detail suitable for professional technicians and advanced DIY enthusiasts
Engine Type:
Inline-six, naturally aspirated
Engine Code:
M103.980 (or similar variant)
Displacement:
2960 cc (3.0 Liters)
Bore X Stroke:
88.5 mm x 80.25 mm
Horsepower Approx:
189 hp @ 5700 rpm
Torque Approx:
260 Nm (192 lb-ft) @ 4400 rpm
Fuel Injection:
Bosch KE-Jetronic (CIS-E) with electronic control unit (ECU)
Fuel Type:
Unleaded gasoline (premium octane recommended)
Ignition System:
Electronic ignition with knock sensor
Coolant Capacity Approx:
8.5 Liters
Type:
4-speed automatic transmission
Torque Converter Lockup:
Yes
Fluid Type:
Dexron III (or equivalent MB approval, e.g., MB 236.1)
Capacity:
2.5 Liters (dry fill), 1.5 Liters (drain and refill)
Length:
Approx. 4740 mm (186.6 inches)
Width:
Approx. 1740 mm (68.5 inches)
Height:
Approx. 1430 mm (56.3 inches)
Curb Weight Approx:
1600-1700 kg (3527-3748 lbs), varies with equipment
Gross Vehicle Weight Rating Approx:
2100-2200 kg (4630-4850 lbs)
Airbags:
Driver's side airbag (standard on later models and optional earlier), passenger airbag not typically standard on this generation
Seatbelts:
3-point inertia-reel seatbelts front and rear
Body Construction:
Integrated safety cage, crumple zones
ABS:
Anti-lock Braking System (ABS) standard
Traction Control:
Traction Control System (ASR - Acceleration Slip Regulation) available on later models
NHTSA Ratings Era:
While specific NHTSA ratings for this era are not readily available in a standardized format comparable to modern tests, Mercedes-Benz vehicles of this period were engineered with a strong emphasis on occupant protection, setting high standards for safety.
Audio System:
Factory premium audio systems, often with cassette players and advanced (for the era) speaker configurations. CD changers were optional.
Climate Control:
Optional automatic climate control (climate control) system with precise temperature regulation.
ABS:
Standard Anti-lock Braking System (ABS) for enhanced braking control.
Traction Control:
Optional Acceleration Slip Regulation (ASR) for improved traction during acceleration, especially on the 4Matic models.
Connectivity Features:
Limited by the era; primarily focused on internal vehicle systems. Aftermarket integration for Bluetooth or aux input is common.
Oil Change Interval:
Approximately every 15,000 km (9,300 miles) or 12 months, whichever comes first, using synthetic oil.
Transmission Service Interval:
Every 50,000-60,000 km (30,000-37,000 miles), including filter and gasket replacement.
Coolant Flush:
Every 2-3 years or as recommended.
Engine Oil Type:
API SJ/SL or ACEA A3/B4; SAE 0W-40, 5W-40, 5W-30, or 10W-40 (refer to manual for specific viscosity recommendations based on climate).
Brake Fluid Type:
DOT 3 or DOT 4 (low viscosity recommended for ABS systems).
Power Steering Fluid:
MB Spec 236.3 (ATF Dexron II or III is often compatible but MB spec is preferred).
Common Problems:
Head gasket leaks, oil leaks (valve cover, oil pan), vacuum hose deterioration, fuel distributor issues, idle control valve problems, wiring harness degradation (especially under-hood), early ABS sensor failures, differential seal leaks on 4Matic models.
Maintenance Focus:
Preventative maintenance is key to the longevity of these vehicles. Regular fluid changes, inspection of rubber components, and timely replacement of worn parts are crucial.
Heritage:
Mercedes-Benz has a long-standing reputation for engineering excellence, safety innovation, and luxury automotive production, dating back to the invention of the automobile.
W124 Generation:
The W124 generation (1984-1995) is highly regarded for its build quality, durability, and sophisticated design. The 300E 4Matic was a key variant, introduced to offer enhanced traction and stability in various conditions.
Production Period:
The W124 chassis was produced from 1984 to 1995. The 300E 4Matic variant specifically ran through the early 1990s, including the years 1990-1993, before being replaced by the E320 4Matic.
Manufacturing Locations:
Primarily Germany, with some assembly in other global locations.
