The Mercedes-Benz W123 is a compact executive car produced from 1976 to 1986, representing a significant evolution in the Mercedes-Benz lineup. Replacing the W114, the W123 established new benchmarks for safety, build quality, and comfort in its class. The 250 model, powered by a 2.5-liter inline-six engine producing 140 horsepower, was a popular variant, particularly in European markets. While not initially a major seller in the United States, the W123 gained a following for its durability and understated elegance, becoming a sought-after classic among enthusiasts.
The Mercedes-Benz W123 250: A Legacy of Engineering
The W123 series was a pivotal model for Mercedes-Benz, solidifying their reputation for engineering excellence. Introduced in September 1979 and continuing through December 1985, the 250 model occupied a sweet spot in the range, offering a balance of performance and fuel efficiency. It was designed to appeal to buyers seeking a comfortable, reliable, and well-engineered vehicle for both daily commuting and long-distance travel. The W123 was available in sedan, coupe, and station wagon (estate) body styles, with the sedan being the most common.
Engine & Performance
The heart of the W123 250 is its 2.5-liter (2525 cm3 or 154.08 cu. in.) inline-six cylinder engine, designated M 123 V 25 / 123.921. This naturally aspirated engine produces 140 horsepower at 5500 rpm and 200 Nm (147.51 lb.-ft.) of torque at 3500 rpm. The engine features a single overhead camshaft (SOHC) valvetrain and a compression ratio of 9:1. Fuel delivery is managed by a carburetor. While not a performance car by modern standards, the 250 offered respectable acceleration, achieving 0-60 mph in approximately 10.7 seconds and a top speed of 185 km/h (114.95 mph). The engine’s power-to-weight ratio is 99.3 HP per tonne, and it delivers 55.4 horsepower per liter of displacement. The drivetrain consists of a rear-wheel drive configuration coupled with a 4-speed manual transmission.
Design & Features
The W123’s design is characterized by its clean lines, robust construction, and emphasis on passenger safety. The sedan body style offers seating for five passengers across four doors. The car’s dimensions are 4725 mm (186.02 in.) in length, 1786 mm (70.31 in.) in width, and 1438 mm (56.61 in.) in height, with a wheelbase of 2795 mm (110.04 in.).
Safety was a key consideration in the W123’s design. It featured crumple zones in the front and rear, a reinforced passenger cell, and disc brakes on all four wheels. The suspension system utilizes a double wishbone setup at the front and a trailing arm configuration at the rear, providing a comfortable ride and stable handling. Interior features, while relatively simple by today’s standards, were well-appointed for the era, with durable materials and a focus on functionality. The car’s curb weight is 1410 kg (3108.52 lbs), with a maximum permissible weight of 1930 kg (4254.92 lbs) and a maximum load capacity of 520 kg (1146.4 lbs). The fuel tank has a capacity of 80 liters (21.13 US gal | 17.6 UK gal).
Technical Specifications
| Brand | Mercedes-Benz |
| Model | W123 |
| Generation | W123 |
| Type (Engine) | 250 (140 Hp) |
| Start of production | September, 1979 |
| End of production | December, 1985 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 16.4 l/100 km (14.3 US mpg, 17.2 UK mpg, 6.1 km/l) |
| Fuel consumption (extra urban) | 9.8 l/100 km (24 US mpg, 28.8 UK mpg, 10.2 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 11.3 sec |
| Acceleration 0 – 62 mph | 11.3 sec |
| Acceleration 0 – 60 mph | 10.7 sec |
| Maximum speed | 185 km/h (114.95 mph) |
| Weight-to-power ratio | 10.1 kg/Hp |
| Weight-to-torque ratio | 7.1 kg/Nm |
| Power | 140 Hp @ 5500 rpm |
| Power per litre | 55.4 Hp/l |
| Torque | 200 Nm @ 3500 rpm (147.51 lb.-ft. @ 3500 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M 123 V 25 / 123.921 |
| Engine displacement | 2525 cm3 (154.08 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 86 mm (3.39 in.) |
| Piston Stroke | 72.45 mm (2.85 in.) |
| Compression ratio | 9:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Carburettor |
| Engine aspiration | Naturally aspirated |
| Valvetrain | SOHC |
| Engine oil capacity | 7.5 l (7.93 US qt | 6.6 UK qt) |
| Coolant capacity | 10 l (10.57 US qt | 8.8 UK qt) |
| Kerb Weight | 1410 kg (3108.52 lbs) |
| Max. weight | 1930 kg (4254.92 lbs) |
| Max load | 520 kg (1146.4 lbs) |
| Fuel tank capacity | 80 l (21.13 US gal | 17.6 UK gal) |
| Length | 4725 mm (186.02 in.) |
| Width | 1786 mm (70.31 in.) |
| Height | 1438 mm (56.61 in.) |
| Wheelbase | 2795 mm (110.04 in.) |
| Front track | 1488 mm (58.58 in.) |
| Rear track | 1446 mm (56.93 in.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears | 4 |
| Gearbox type | Manual transmission |
| Front suspension | Double wishbone |
| Rear suspension | Trailing arm |
| Front brakes | Disc |
| Rear brakes | Disc |
| Steering type | Cone worm with recirculation balls |
| Wheel rims size | 5.5J x 14 |
The Mercedes-Benz W123 250 remains a highly regarded vehicle, celebrated for its robust engineering, comfortable ride, and timeless design. Its enduring popularity among collectors and enthusiasts is a testament to the quality and craftsmanship that defined Mercedes-Benz during this era.
