The Mercedes-Benz S 320 Long, produced from March 1994 to September 1998, represented a significant evolution of the W140 S-Class, often referred to as the facelift model. Positioned as a mid-range offering within the long-wheelbase S-Class lineup, it bridged the gap between the entry-level S 280 and the flagship S 420 and S 500 models. This variant aimed to deliver a balance of performance, luxury, and fuel efficiency, appealing to buyers who desired the prestige of an S-Class without the higher price tag of the top-tier trims. The “Long” designation indicated an extended wheelbase, providing increased rear passenger legroom – a key feature for the S-Class’s target demographic.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | S-class |
| Generation | S-class Long (V140, facelift 1994) |
| Type (Engine) | S 320 (231 Hp) 5G-TRONIC |
| Start of production | March, 1994 |
| End of production | September, 1998 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (economy) – urban (NEDC) | 19.3 l/100 km (12.2 US mpg, 14.6 UK mpg, 5.2 km/l) |
| Fuel consumption (economy) – extra urban (NEDC) | 10 l/100 km (23.5 US mpg, 28.2 UK mpg, 10 km/l) |
| Fuel consumption (economy) – combined (NEDC) | 13.4 l/100 km (17.6 US mpg, 21.1 UK mpg, 7.5 km/l) |
| CO2 emissions (NEDC) | 317 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 8.9 sec |
| Acceleration 0 – 62 mph | 8.9 sec |
| Acceleration 0 – 60 mph | 8.5 sec |
| Maximum speed | 225 km/h (139.81 mph) |
| Weight-to-power ratio | 8.3 kg/Hp, 120.3 Hp/tonne |
| Weight-to-torque ratio | 6.1 kg/Nm, 164.1 Nm/tonne |
| Power | 231 Hp @ 5600 rpm |
| Power per litre | 72.2 Hp/l |
| Torque | 315 Nm @ 3750 rpm (232.33 lb.-ft. @ 3750 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M 104.994 |
| Engine displacement | 3199 cm3 (195.21 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 89.9 mm (3.54 in.) |
| Piston Stroke | 84 mm (3.31 in.) |
| Compression ratio | 10:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | DOHC |
| Engine oil capacity | 7 l (7.4 US qt | 6.16 UK qt) |
| Coolant | 14.5 l (15.32 US qt | 12.76 UK qt) |
| Kerb Weight | 1920 kg (4232.88 lbs.) |
| Max. weight | 2580 kg (5687.93 lbs.) |
| Max load | 660 kg (1455.05 lbs.) |
| Trunk (boot) space – minimum | 525 l (18.54 cu. ft.) |
| Fuel tank capacity | 100 l (26.42 US gal | 22 UK gal) |
| Length | 5213 mm (205.24 in.) |
| Width | 1886 mm (74.25 in.) |
| Height | 1486 mm (58.5 in.) |
| Wheelbase | 3140 mm (123.62 in.) |
| Front track | 1606 mm (63.23 in.) |
| Rear (Back) track | 1579 mm (62.17 in.) |
| Minimum turning circle | 12.51 m (41.04 ft.) |
| 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 | 5 gears, automatic transmission G-TRONIC |
| Front suspension | Coil spring, Double wishbone, Transverse stabilizer |
| Rear suspension | Independent multi-link suspension, Transverse stabilizer, Coil spring |
| 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 | 235/60 R16 |
| Wheel rims size | 7.5J x 16 |
Powertrain & Engine Architecture
The S 320 Long was powered by the M104.994 3.2-liter inline-six engine. This engine was a cornerstone of Mercedes-Benz’s mid-range offerings throughout the 1990s, known for its smoothness and reliability. It featured a cast iron block and aluminum cylinder head, employing multi-port fuel injection and a double overhead camshaft (DOHC) valvetrain with four valves per cylinder. The engine produced 231 horsepower at 5600 rpm and 315 Nm (232 lb-ft) of torque at 3750 rpm. Paired with the engine was the 5G-TRONIC automatic transmission, a five-speed unit that offered smooth and refined gear changes. This transmission was electronically controlled, adapting shift points based on driving conditions and throttle input. The 5G-TRONIC was a significant advancement over previous Mercedes-Benz automatic transmissions, contributing to improved fuel efficiency and driving comfort.
Driving Characteristics
The S 320 Long, with its automatic transmission, offered a comfortable and relaxed driving experience. Acceleration from 0 to 60 mph took approximately 8.5 seconds, and top speed was electronically limited to 139.81 mph. While not a sports car, the engine provided sufficient power for effortless cruising and overtaking. The automatic transmission’s gear ratios were tuned for smooth operation and fuel economy, rather than outright performance. Compared to the more powerful S 420 or S 500, the S 320 felt less urgent in its acceleration, but it offered a more manageable and fuel-efficient driving experience. The longer wheelbase of the “Long” variant contributed to a more stable and comfortable ride, particularly noticeable on highway journeys.
Equipment & Trim Levels
The S 320 Long came standard with a comprehensive list of luxury features, befitting its status as a flagship sedan. These included leather upholstery, power-adjustable front seats with memory function, automatic climate control, a premium sound system, and wood trim throughout the cabin. Optional extras included a rear entertainment system, heated seats (front and rear), a sunroof, and upgraded leather options. The interior design emphasized elegance and sophistication, with a focus on high-quality materials and craftsmanship. The dashboard layout was typical of the W140 S-Class, featuring a combination of analog gauges and a central information display.
Chassis & Braking
The S 320 Long featured a robust chassis with independent suspension at all four wheels. The front suspension utilized coil springs and double wishbones, while the rear suspension employed a multi-link design. Both ends were equipped with a transverse stabilizer bar to reduce body roll. Braking duties were handled by ventilated discs at the front and solid discs at the rear, assisted by an Anti-lock Braking System (ABS). The suspension was tuned for comfort, providing a smooth and controlled ride. The steering was a recirculating ball system with hydraulic power assistance, offering precise and responsive handling.
Market Reception & Comparison
The S 320 Long was generally well-received by automotive critics. It was praised for its comfortable ride, refined interior, and smooth powertrain. However, some critics noted that its performance was not as exhilarating as that of the higher-powered S-Class models. Fuel economy, while respectable for a large luxury sedan, was still relatively high at 17.6 US mpg combined. Compared to the S 280, the S 320 offered a significant performance upgrade, while remaining more affordable than the S 420 or S 500. The S 320 Long appealed to buyers who prioritized comfort, luxury, and prestige over outright performance.
Legacy
The M104 engine, found in the S 320 Long, is known for its durability and longevity. With proper maintenance, these engines can reliably exceed 200,000 miles. The 5G-TRONIC transmission is also generally considered to be a robust unit, although it may require occasional servicing. In the used car market today, the W140 S-Class, including the S 320 Long, is gaining popularity among collectors and enthusiasts. These cars are appreciated for their build quality, luxurious features, and classic styling. While maintenance costs can be higher than for more modern vehicles, the S 320 Long offers a unique and rewarding ownership experience.
