Segment:
Mid-size Luxury Sedan
Target Audience:
Discerning buyers seeking durability, comfort, and German engineering
Key Competitors:
BMW 5 Series (E28/E34), Audi 100/200, Volvo 740/760
Distinguishing Factors:
Exceptional build quality, legendary durability, smooth ride, diesel efficiency
Design:
Timeless W124 chassis design, robust construction
Powertrain:
Robust OM603.960 3.0L turbocharged diesel engine known for longevity
Ride Quality:
Sophisticated independent suspension system providing a refined ride
Safety:
Early adoption of safety features like crumple zones and ABS (optional)
Primary Coverage:
Repair, Maintenance, Troubleshooting, Diagnostics
Scope:
Comprehensive vehicle service and repair
Estimated Pages:
High (Detailed service manuals typically range from 1000+ pages)
Type:
Workshop Service Repair Manual (WSRM)
Software Requirement:
None (Standard PDF reader)
Engine:
OM603.960 Turbo Diesel (Engine overhaul, fuel injection, turbocharger, cooling, lubrication)
Transmission:
Automatic (4-speed 722.3) and Manual (5-speed 717.4) transmission service and repair
Drivetrain:
Front suspension, rear suspension, driveshaft, differentials
Brakes:
Hydraulic brake system, ABS (Anti-lock Braking System) if equipped
Steering:
Power assisted steering system
Electrical:
Wiring diagrams, lighting, charging system, starting system, instrument cluster, climate control
Bodywork:
Exterior panels, interior trim, doors, windows, sunroof
Climate Control:
HVAC system, R134a conversion (if applicable), heater core, air conditioning
Fuel System:
Diesel injection pump, injectors, fuel tank, lines
Exhaust System:
Exhaust manifolds, catalytic converter (if equipped), muffler
Maintenance:
Routine service, oil changes, filter replacements, fluid checks and changes
Troubleshooting:
Diagnostic charts and procedures for common issues
Repair:
Detailed step-by-step repair instructions for all major components
Overhaul:
Engine, transmission, and differential rebuild procedures
Adjustments:
Valve adjustments, injection timing, parking brake adjustments
Diagnostics:
Component testing, electrical circuit analysis, fault code interpretation (if applicable)
Depth:
Comprehensive (Suitable for professional technicians and advanced DIYers)
Detail Level:
Component-level disassembly and reassembly, torque specifications, clearances
Engine Type:
Inline-6 Cylinder, Turbocharged Diesel
Bore X Stroke:
87.0 mm x 84.0 mm
Compression Ratio:
21.0:1
Horsepower:
148 hp @ 4600 rpm (approx.)
Torque:
235 lb-ft @ 2400 rpm (approx.)
Injection System:
Bosch VE Rotary Injection Pump
Turbocharger:
Garrett or MHI turbocharger
Wheelbase:
110.4 inches (2804 mm)
Length:
189.1 inches (4803 mm)
Width:
69.4 inches (1763 mm)
Height:
56.1 inches (1425 mm)
Curb Weight:
3,505 lbs (1590 kg) approx.
Gross Vehicle Weight Rating:
4,740 lbs (2150 kg) approx.
Towing Capacity:
Refer to owner's manual (typically limited for chassis design)
Crash Test Results:
NHTSA ratings not readily available for this era; known for robust structural integrity.
ABS:
Optional Anti-lock Braking System (ABS)
Traction Control:
Not typically available on this model
Airbags:
Driver-side airbag standard from 1987; early models may not have it.
Seatbelts:
3-point inertia-reel seatbelts front and rear
Structure:
Reinforced passenger cell, energy-absorbing steering column, side-impact protection
Radio:
Factory AM/FM cassette player with optional CD changer.
Speakers:
Typically 4 or 6 speaker system.
Cruise Control:
Standard cruise control system.
Bluetooth:
Not available (requires aftermarket installation)
Aux Input:
Not available (requires aftermarket installation)
Oil Change Interval:
Every 7,500 miles or 12,000 km (Diesel specific oils recommended)
Air Filter Replacement:
Every 15,000 miles or 24,000 km, or as needed based on operating conditions.
Fuel Filter Replacement:
Every 30,000 miles or 48,000 km
Transmission Fluid Change:
Every 30,000 miles or 48,000 km (Automatic and Manual)
Engine Oil:
API CD or CE rated Diesel Engine Oil, SAE 15W-40 or 10W-40 depending on climate. Check manual for exact spec.
Coolant:
MB 325.0 (Antifreeze/Coolant Concentrate), typically a 50/50 mix with distilled water.
Brake Fluid:
DOT 3 or DOT 4
Power Steering Fluid:
MB 236.3 (ATF Dexron II or equivalent)
Automatic Transmission Fluid:
MB 236.3 (ATF Dexron II or equivalent)
Diesel Specific:
Glow plug issues, injection pump leaks, vacuum leaks affecting engine performance, thermostat failures.
General W124:
Headliner sagging, blower motor resistor failure, vacuum accumulator leaks, coolant leak points (e.g., heater valve, hoses), differential seal leaks, rust in common areas (wheel arches, rocker panels).
Electrical:
Wire harness degradation (especially in early models), SRS warning light issues, climate control module failures.
Brand Legacy:
Mercedes-Benz known for engineering excellence, luxury, and durability.
W124 Generation:
Introduced in 1984, replaced the W123. The 300D Turbo was a popular, refined diesel variant.
Engine Development:
The OM603 engine represented an evolution of Mercedes-Benz's inline-6 diesel technology, featuring turbocharging for improved performance and efficiency.
Manufacturing Location:
Germany
Sales Volume Context:
Part of a highly successful and long-running model line for Mercedes-Benz.
Industry Accolades:
The W124 chassis is widely recognized for its build quality and durability, often cited in automotive enthusiast circles as one of the best Mercedes-Benz models ever produced.
Consumer Reports:
Consistently rated highly for reliability and owner satisfaction in its era.
Safety Standards:
Meets all relevant safety and emissions standards for the model years in its respective markets.
