The Mercedes-Benz S 320, part of the W140 generation S-Class produced from 1994 to 1998, represented a significant evolution in luxury and technology for the German automaker. Positioned as a mid-range offering within the W140 lineup – which also included the S 280, S 420, S 500, and later the S 600 – the S 320 struck a balance between performance, refinement, and cost. The “facelift” models from 1994 onwards featured subtle styling revisions and improvements to the interior, solidifying the W140’s reputation as a technologically advanced and exceptionally comfortable grand tourer. This variant was primarily aimed at buyers seeking a sophisticated and powerful vehicle without the outright expense of the flagship models.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | S-class |
| Generation | S-class (W140, facelift 1994) |
| Type (Engine) | S 320 (231 Hp) 5G-TRONIC |
| Start of production | March, 1994 |
| End of production | August, 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, 120.9 Hp/tonne |
| Weight-to-torque ratio | 6.1 kg/Nm, 164.9 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 | 1910 kg (4210.83 lbs.) |
| Max. weight | 2570 kg (5665.88 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 | 5113 mm (201.3 in.) |
| Width | 1886 mm (74.25 in.) |
| Height | 1486 mm (58.5 in.) |
| Wheelbase | 3040 mm (119.69 in.) |
| Front track | 1606 mm (63.23 in.) |
| Rear (Back) track | 1579 mm (62.17 in.) |
| Minimum turning circle | 12.18 m (39.96 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| 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 was powered by the M104.994 3.2-liter inline-six engine. This engine was a significant departure from Mercedes-Benz’s traditional V8 offerings, representing a move towards more efficient and technologically advanced powertrains. The M104 featured a cast iron block with an aluminum cylinder head, dual overhead camshafts (DOHC), and four valves per cylinder. Fuel delivery was handled by a Bosch Motronic multi-port fuel injection system, optimizing combustion for both power and economy. 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 known for its smooth shifting and adaptability. This transmission was electronically controlled, further enhancing its responsiveness and efficiency.
Driving Characteristics
The S 320’s driving experience was characterized by a blend of effortless cruising and respectable performance. While not as overtly powerful as the V8-equipped S 420 or S 500, the inline-six provided ample power for everyday driving and highway passing. The 5G-TRONIC transmission contributed to a relaxed driving experience, with well-spaced gear ratios that kept the engine in its optimal power band. Acceleration from 0 to 60 mph took approximately 8.5 seconds, and the car had a top speed of 139.81 mph. Compared to the manual transmission options available on other S-Class models, the automatic prioritized comfort and ease of use over outright sportiness. The inline-six engine also offered a smoother and quieter operation than the V8s, enhancing the overall refinement of the driving experience.
Equipment & Trim Levels
The S 320 came standard with a comprehensive array 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 were plentiful, including a rear seat entertainment system, a sunroof, and upgraded leather options. The interior design was characterized by its understated elegance and high-quality materials. The S 320’s dashboard featured a clean and intuitive layout, with easy-to-read gauges and logically placed controls.
Chassis & Braking
The W140 S-Class featured a robust chassis designed for both comfort and handling. The S 320 utilized a coil spring, double wishbone suspension at the front and an independent multi-link suspension at the rear, providing a smooth and controlled ride. Stabilizer bars were fitted to both axles to reduce body roll during cornering. 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 steering was a recirculating ball system with hydraulic power assistance, offering a balance of precision and ease of use.
Market Reception & Comparison
The S 320 was generally well-received by automotive critics, who praised its blend of luxury, performance, and technology. It was seen as a sensible alternative to the more expensive V8 models, offering a similar level of refinement at a lower price point. Fuel economy, while not exceptional by modern standards, was considered reasonable for a vehicle of its size and class. Compared to the S 280, the S 320 offered a significant performance upgrade, while the S 420 and S 500 provided even more power but at a higher cost. Reliability was generally good, although the W140 S-Class was known for its complex systems, which could be expensive to repair.
Legacy
The W140 S-Class, including the S 320 variant, is now considered a classic car and a testament to Mercedes-Benz’s engineering prowess. The M104 engine is known for its durability and longevity, and well-maintained examples can still provide years of reliable service. The 5G-TRONIC transmission, while sophisticated for its time, can require specialized maintenance. Today, the S 320 is a sought-after vehicle among collectors and enthusiasts, appreciated for its timeless design, luxurious interior, and smooth driving experience. Finding well-preserved examples can be challenging, but the S 320 remains a compelling choice for those seeking a classic luxury sedan.
