The Mercedes-Benz 420 SE, part of the W126 S-Class range produced from 1985 to 1987, represented a significant evolution of the flagship sedan. Following the 1985 facelift, the 420 SE occupied a sweet spot in the lineup, offering a blend of luxury, performance, and refinement. It sat above the 280 SE and 380 SE models, providing a more powerful and sophisticated experience, while remaining below the range-topping 560 SE. This variant was primarily aimed at the North American and European markets, where buyers desired a large, comfortable, and prestigious vehicle capable of long-distance cruising.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | S-class |
| Generation | S-class SE (W126, facelift 1985) |
| Type (Engine) | 420 SE V8 (218 Hp) Automatic |
| Start of production | June, 1985 |
| End of production | September, 1987 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 14.6 l/100 km (16.1 US mpg, 19.3 UK mpg, 6.8 km/l) |
| Fuel consumption (extra urban) | 8.9 l/100 km (26.4 US mpg, 31.7 UK mpg, 11.2 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 8.3 sec |
| Acceleration 0 – 62 mph | 8.3 sec |
| Acceleration 0 – 60 mph | 7.9 sec |
| Maximum speed | 218 km/h (135.46 mph) |
| Weight-to-power ratio | 7.3 kg/Hp, 136.3 Hp/tonne |
| Weight-to-torque ratio | 4.8 kg/Nm, 206.3 Nm/tonne |
| Power | 218 Hp @ 5200 rpm |
| Power per litre | 52 Hp/l |
| Torque | 330 Nm @ 3750 rpm (243.4 lb.-ft. @ 3750 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M 116 E 42 / 116.965 |
| Engine displacement | 4196 cm3 (256.06 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 92 mm (3.62 in.) |
| Piston Stroke | 78.9 mm (3.11 in.) |
| Compression ratio | 9:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | SOHC |
| Engine oil capacity | 8 l (8.45 US qt | 7.04 UK qt) |
| Coolant | 12.5 l (13.21 US qt | 11 UK qt) |
| Kerb Weight | 1600 kg (3527.4 lbs.) |
| Max. weight | 2120 kg (4673.8 lbs.) |
| Max load | 520 kg (1146.4 lbs.) |
| Fuel tank capacity | 90 l (23.78 US gal | 19.8 UK gal) |
| Length | 5020 mm (197.64 in.) |
| Width | 1820 mm (71.65 in.) |
| Height | 1437 mm (56.57 in.) |
| Wheelbase | 2930 mm (115.35 in.) |
| Front track | 1555 mm (61.22 in.) |
| Rear track | 1527 mm (60.12 in.) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 4 gears, automatic transmission |
| Front suspension | Double wishbone |
| Rear suspension | Trailing arm |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Power steering | Hydraulic Steering |
| Tires size | Front wheel tires: 205/65 R15Rear wheel tires: 205/65 R15 |
| Wheel rims size | Front wheel rims: 7J x 15Rear wheel rims: 7J x 15 |
INTRODUCTION
The W126 S-Class, introduced in 1979, quickly became synonymous with German engineering and luxury. The 1985 facelift brought subtle but important changes, including revised styling, improved aerodynamics, and updated technology. The 420 SE, powered by the M116 E42 engine, was a key component of this revised lineup. It offered a significant step up in performance from the six-cylinder 280 SE and 380 SE models, while providing a more accessible price point than the top-of-the-line 560 SE. The 420 SE was designed for discerning buyers who valued a smooth, powerful, and refined driving experience.
Powertrain & Engine Architecture
The heart of the 420 SE is the M116 E42 4.2-liter V8 engine. This engine, a cornerstone of Mercedes-Benz’s engineering prowess, features a cast-iron block and aluminum cylinder heads. It utilizes a single overhead camshaft (SOHC) design with two valves per cylinder. Fuel delivery is managed by a Bosch K-Jetronic multi-port fuel injection system, known for its reliability and precise metering. The engine produces 218 horsepower at 5200 rpm and 330 Nm (243.4 lb-ft) of torque at 3750 rpm. Paired with the engine is a four-speed automatic transmission, specifically the 722.3 series, known for its smooth shifts and durability. This transmission was designed to handle the V8’s power output while providing a comfortable driving experience.
Driving Characteristics
The 420 SE’s driving experience is characterized by its smooth and effortless power delivery. The automatic transmission, while not offering the quickest shifts by modern standards, provides seamless gear changes that complement the V8’s torque. Acceleration from 0 to 60 mph takes approximately 7.9 seconds, and the car can reach a top speed of 218 km/h (135.46 mph). Compared to the 280 SE or 380 SE, the 420 SE offers noticeably stronger acceleration and a more confident feel when overtaking. While the 560 SE provides even greater performance, the 420 SE strikes a balance between power and fuel economy. The steering is relatively heavy, typical of Mercedes-Benz vehicles of this era, providing a sense of solidity and control.
Equipment & Trim Levels
The 420 SE came standard with a comprehensive list of luxury features. These included power windows, power locks, a sunroof, leather upholstery, and climate control. Wood trim adorned the interior, adding to the sense of opulence. Optional extras included a premium sound system, heated seats, and a self-leveling suspension system. The interior layout was classic Mercedes-Benz, emphasizing comfort and functionality. The dashboard featured a clear and concise instrument cluster, and the seats were designed for long-distance comfort.
Chassis & Braking
The W126 S-Class features a robust chassis with independent suspension all around. The front suspension utilizes a double wishbone design, while the rear employs a trailing arm setup. This configuration provides a comfortable ride and good handling characteristics. The 420 SE is equipped with ventilated disc brakes at the front and solid discs at the rear. An Anti-lock Braking System (ABS) was standard, enhancing safety and control during hard braking. The steering system is a cone worm with recirculation balls, providing a stable and predictable feel.
Market Reception & Comparison
The 420 SE was well-received by critics and buyers alike. It was praised for its smooth ride, powerful engine, and luxurious interior. Compared to the 280 SE and 380 SE, the 420 SE offered a significant performance upgrade without the higher price tag of the 560 SE. Fuel economy, while not a primary concern for S-Class buyers, was reasonable for a V8-powered luxury sedan. Reliability was generally good, although maintenance costs could be substantial due to the complexity of the vehicle. The 420 SE was often seen as the “sweet spot” in the W126 lineup, offering a compelling combination of performance, luxury, and value.
Legacy
Today, the W126 S-Class, including the 420 SE, is considered a classic Mercedes-Benz. These cars are sought after by collectors and enthusiasts for their timeless design, robust engineering, and luxurious appointments. The M116 engine, while aging, is known for its durability when properly maintained. Finding well-preserved examples can be challenging, as many have suffered from neglect or have been modified over the years. However, a well-maintained 420 SE remains a rewarding vehicle to own and drive, offering a glimpse into the golden age of German luxury automobiles. Parts availability is generally good, although some specific components can be difficult to source.
