Mercedes-Benz W124 300 D (109 Hp)

The Mercedes-Benz W124 300 D represents a pivotal point in the manufacturer’s mid-size sedan lineage, produced from March 1984 to August 1989. Part of the W124 series, it was designed as a replacement for the W201 (190E) and W123 models, offering a blend of luxury, durability, and advanced engineering for its time. The 300 D, specifically, was a diesel-powered variant aimed at buyers prioritizing fuel efficiency and longevity. While not initially a high-volume seller in the United States due to evolving emissions regulations and a growing preference for gasoline engines, the W124 series, and the 300 D in particular, gained a strong reputation for its build quality and reliability, becoming a sought-after classic among enthusiasts.

The Mercedes-Benz W124 300 D: A Legacy of Engineering

The W124 series was a significant departure from its predecessors, incorporating substantial improvements in safety, comfort, and overall refinement. Mercedes-Benz invested heavily in research and development, resulting in a vehicle that set new standards for its class. The 300 D, powered by a robust inline-six diesel engine, offered a compelling alternative to gasoline-powered competitors, particularly in European markets where diesel fuel was more affordable and readily available. Its design prioritized passenger safety, featuring a reinforced passenger cell and crumple zones, innovations that were relatively advanced for the mid-1980s.

Engine & Performance

The heart of the W124 300 D is its 3.0-liter (2996 cm³) inline-six cylinder diesel engine, designated the OM 603 D 30 / 603.912. This engine produces 109 horsepower at 5000 rpm and 210 Nm (154.89 lb.-ft.) of torque at 2200 rpm. While the horsepower figure might seem modest by modern standards, the engine’s torque delivery provides strong low-end and mid-range acceleration, making it well-suited for long-distance cruising and hauling passengers. The engine utilizes precombustion chamber injection, a technology common in Mercedes-Benz diesels of the era, to improve combustion efficiency and reduce emissions. Acceleration from 0 to 100 km/h (0-62 mph) takes approximately 13.7 seconds, and it achieves a maximum speed of 190 km/h (118.06 mph). Fuel economy is a strong point, with combined cycle consumption rated at 7.4 l/100 km (31.8 US mpg, 38.2 UK mpg). The engine’s longitudinal front-engine layout contributes to balanced handling characteristics. A five-speed manual transmission was standard, providing drivers with precise control over the powertrain.

Design & Features

The W124 300 D is a four-door sedan with a classic, understated design. Its body lines are characterized by clean surfaces, a relatively upright stance, and a focus on aerodynamic efficiency. The interior is spacious and well-appointed, offering comfortable seating for five passengers. The dashboard layout is functional and ergonomically designed, with clear instrumentation and easy-to-reach controls. Features included power steering (hydraulic), disc brakes on all four wheels, and a robust suspension system – wishbone front suspension and independent multi-link coil spring rear suspension – designed to provide a comfortable ride and stable handling. Safety features, while not as comprehensive as those found in modern vehicles, were advanced for the time and included a reinforced passenger cell and crumple zones. The trunk offers a generous 520 liters (18.36 cu. ft.) of storage space. The W124’s build quality is renowned, with attention paid to detail and the use of high-quality materials, contributing to its longevity and enduring appeal.

Technical Specifications

BrandMercedes-Benz
ModelW124
GenerationW124
Type (Engine)300 D (109 Hp)
Start of productionMarch, 1984
End of productionAugust, 1989
Powertrain ArchitectureInternal Combustion engine
Body typeSedan
Seats5
Doors4
Fuel consumption (urban)9.8 l/100 km (24 US mpg, 28.8 UK mpg, 10.2 km/l)
Fuel consumption (extra urban)5.4 l/100 km (43.6 US mpg, 52.3 UK mpg, 18.5 km/l)
Fuel consumption (combined)7.4 l/100 km (31.8 US mpg, 38.2 UK mpg, 13.5 km/l)
Fuel TypeDiesel
Acceleration 0 – 100 km/h13.7 sec
Acceleration 0 – 62 mph13.7 sec
Acceleration 0 – 60 mph13 sec
Maximum speed190 km/h (118.06 mph)
Weight-to-power ratio14.3 kg/Hp, 69.9 Hp/tonne
Weight-to-torque ratio7.4 kg/Nm, 134.6 Nm/tonne
Power109 Hp @ 5000 rpm
Power per litre36.4 Hp/l
Torque210 Nm @ 2200 rpm (154.89 lb.-ft. @ 2200 rpm)
Engine layoutFront, Longitudinal
Engine Model/CodeOM 603 D 30 / 603.912
Engine displacement2996 cm³ (182.83 cu. in.)
Number of cylinders6
Engine configurationInline
Cylinder Bore87 mm (3.43 in.)
Piston Stroke84 mm (3.31 in.)
Compression ratio22:1
Number of valves per cylinder2
Fuel injection systemPrecombustion chamber injection
Engine aspirationNaturally aspirated engine
ValvetrainSOHC
Engine oil capacity7.5 l (7.93 US qt | 6.6 UK qt)
Coolant9.5 l (10.04 US qt | 8.36 UK qt)
Kerb Weight1560 kg (3439.21 lbs.)
Max. weight2050 kg (4519.48 lbs.)
Max load490 kg (1080.27 lbs.)
Trunk (boot) space – minimum520 l (18.36 cu. ft.)
Fuel tank capacity70 l (18.49 US gal | 15.4 UK gal)
Length4740 mm (186.61 in.)
Width1740 mm (68.5 in.)
Height1431 mm (56.34 in.)
Wheelbase2800 mm (110.24 in.)
Front track1501 mm (59.09 in.)
Rear (Back) track1491 mm (58.7 in.)
Drivetrain ArchitectureRear wheel drive
Number of gears and type of gearbox5 gears, manual transmission
Front suspensionWishbone
Rear suspensionIndependent multi-link suspension, Coil spring
Front brakesDisc
Rear brakesDisc
Steering typeCone worm with recirculation balls
Power steeringHydraulic Steering
Tires sizeFront wheel tires: 195/65 R15Rear wheel tires: 195/65 R15
Wheel rims sizeFront wheel rims: 6.5J x 15Rear wheel rims: 6.5J x 15

The Mercedes-Benz W124 300 D remains a highly regarded vehicle, celebrated for its engineering excellence, durability, and timeless design. Its robust diesel engine and comfortable ride continue to appeal to enthusiasts and collectors, ensuring its place as a significant model in Mercedes-Benz history.

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