Segment:
Executive Mid-size Sedan/Coupe/Estate/Cabriolet
Competitors:
BMW 5 Series (E28, E34), Audi 100/200 (C3, C4), Volvo 700/900 Series, Saab 9000, Lexus LS400 (later models)
Defining Characteristics:
Exceptional build quality, robust engineering, longevity, sophisticated design, comfortable ride, strong safety features, available with a wide range of gasoline and diesel engines.
Engine Systems:
Engine mechanicals (M102, M103, M104, OM601, OM602, OM603), Fuel injection (KE-Jetronic, HFM, EDC), Ignition systems, Cooling systems, Lubrication systems, Exhaust systems
Transmission Systems:
Manual transmissions (4-speed, 5-speed), Automatic transmissions (4-speed 722.3, 4-speed 722.4, 5-speed 722.5), Hydraulic controls, Electronic controls (ECT)
Chassis Systems:
Suspension (front & rear), Steering system (power steering, steering box/rack), Brakes (ABS, SBC, disc/drum variations), Drivetrain (differentials, axles, driveshafts)
Electrical Systems:
Wiring diagrams, Lighting, Instrumentation, Wiper/washer systems, Horn, Power windows, Power seats, Central locking, Cruise control, Climate control, Audio systems, Engine control units (ECU), ABS control units
Body Systems:
Body shell, Doors, Windows, Seats, Interior trim, Exterior trim, Sunroof, Convertible top (for A124), Corrosion protection
Maintenance Procedures:
Oil changes, filter replacements, spark plug replacement, coolant flushing, brake fluid flush, belt inspection/replacement, battery maintenance, air filter replacement, fuel filter replacement
Repair Procedures:
Engine component rebuilds (cylinder head, pistons, crankshaft), transmission overhaul, brake caliper replacement, suspension component replacement (struts, ball joints, control arms), steering rack repair, fuel injector replacement, power steering pump replacement, radiator replacement
Diagnostics Troubleshooting:
Fault code interpretation (where applicable), symptom-based troubleshooting guides, diagnostic flowcharts, common problem identification and solutions
Depth:
Comprehensive (from basic maintenance to complete engine/transmission overhauls and complex electrical diagnostics)
Engine Family Examples:
M102 (2.0L, 2.3L inline-4), M103 (2.6L, 3.0L inline-6), M104 (2.8L, 3.2L inline-6), OM601 (2.0L inline-4 Diesel), OM602 (2.5L, 2.9L inline-5 Diesel), OM603 (3.0L inline-6 Diesel)
Typical Horsepower Range:
90 HP (OM601 Diesel) - 231 HP (M104 E32 AMG)
Typical Torque Range:
140 Nm (OM601 Diesel) - 345 Nm (M104 E32 AMG)
Fuel Delivery Examples:
Bosch K-Jetronic mechanical fuel injection, Bosch KE-Jetronic (CIS-E) electronic fuel injection, Bosch HFM (Hot Film Air Mass) sequential injection, Bosch EDC (Electronic Diesel Control)
Standard Transmission:
4-speed manual (early models), 5-speed manual (later models)
Optional Transmission:
4-speed automatic (722.3, 722.4), 5-speed automatic (722.5)
Automatic Features:
Hydraulically controlled, often with Comfort/Economy modes, later models featured electronic control for smoother shifts and better fuel economy.
Safety Approvals:
Generally considered very safe for its era, excellent crashworthiness for the time. No standardized NCAP ratings for this period, but internally and in various tests, it performed exceptionally well.
Active Safety Features:
Optional Anti-lock Braking System (ABS) widely available, strong disc brakes all around, precise steering.
Passive Safety Features:
Reinforced safety cell, impact-absorbing crumple zones, dual front airbags (optional on many models, standard on later high-end trims), seatbelt pre-tensioners, side-impact protection beams.
Infotainment Features:
Factory-fitted premium sound systems (often Becker), cassette players, optional CD changers, manual or automatic climate control.
Driver Assistance Features:
ABS (Anti-lock Braking System), Cruise Control (Tempomat), optional Traction Control System (ASR) on some later models, self-leveling suspension (Estate models).
Connectivity Features:
Limited by era; primarily factory radio and speaker systems. Early forms of remote central locking and power accessories. No Bluetooth or Wi-Fi connectivity.
Oil Change Interval:
Typically every 10,000-15,000 km (6,000-9,000 miles) or 12 months, depending on oil type and driving conditions. Consult specific manual for exact intervals.
Major Service Intervals:
Spark plugs: 50,000-100,000 km. Coolant flush: 2-4 years. Brake fluid: 2 years. Transmission fluid/filter: Varies significantly by transmission type and driving, often 60,000-100,000 km for automatics.
Engine Oil Specification:
MB 229.1 or 229.3 compliant oils, typically 0W-40, 5W-40, 5W-30, or 10W-40 depending on climate and engine. Consult manual for exact viscosity and spec.
Transmission Fluid Automatic:
MB 236.6 or 236.7 (e.g., Shell ATF Dexron II E, Texaco ETL-7045E). Specific type varies by transmission model (722.3, 722.4, 722.5).
Coolant Specification:
MB 325.0 or 326.0 compliant coolant (typically ethylene glycol-based with silicate inhibitors), mixed 50/50 with distilled water.
Common Wear Items:
Wiring harness insulation degradation (especially on M104 engines), vacuum hose deterioration, differential seals, fuel pump relay failure, door seal perishing, heater core leaks, rear axle subframe bushings.
Common Engine Issues:
Head gasket leaks (M104), OVP relay failure (impedes fuel injection/ignition), timing chain stretch (high mileage M103/M104), idle control valve issues.
Common Transmission Issues:
Solenoid failures in automatic transmissions, torque converter seal leaks, linkage wear (manual).
Mercedes Benz Legacy:
Mercedes-Benz has a long-standing reputation for building durable, high-quality, and technologically advanced vehicles since its inception.
W124 Development:
The W124 was developed as the successor to the W123 series, aiming to set new benchmarks in engineering, aerodynamics, and safety. It was one of the most over-engineered cars of its time.
Production Period:
1984-1995 (globally, with core production of the 124 Series ending around 1993 for major markets, but continuing in some regions)
Production Locations:
Germany (Sindelfingen, Bremen), Austria, South Africa, other assembly plants.
Automotive Journalism Acclaim:
Consistently lauded by automotive journalists and critics for its engineering, durability, and refinement. Often cited as one of the greatest cars of the 20th century. Won numerous awards for reliability and build quality in its time.
Reliability Rankings:
Extremely high reliability and longevity, considered a benchmark for the era. Many examples remain in regular use decades later.
Manufacturing Standards:
Built to stringent Mercedes-Benz internal quality and durability standards.
