The Mercedes-Benz S 320, part of the long-wheelbase (V140) S-Class range produced from March 1994 to May 1996, represented a significant evolution in luxury automotive engineering. Positioned as a mid-range offering within the V140 lineup – which also included the S 280, S 420, and the high-performance S 500 – the S 320 aimed to deliver a balance of performance, refinement, and technological innovation. The V140 generation, known for its robust build quality and advanced features, solidified the S-Class’s reputation as a benchmark for luxury sedans. This particular variant, coupled with the 4G-TRONIC automatic transmission, was a popular choice for buyers seeking a comfortable and capable grand tourer.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | S-class |
| Generation | S-class Long (V140, facelift 1994) |
| Type (Engine) | S 320 (231 Hp) 4G-TRONIC |
| Start of production | March, 1994 |
| End of production | May, 1996 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 14.5 l/100 km (16.2 US mpg, 19.5 UK mpg) |
| Fuel consumption (extra urban) | 9.6-11.6 l/100 km (24.5 – 20.3 US mpg, 29.4 – 24.4 UK mpg) |
| 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 | 8.2 kg/Hp, 121.6 Hp/tonne |
| Weight-to-torque ratio | 6 kg/Nm, 165.8 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 | 1900 kg (4188.78 lbs.) |
| Max. weight | 2560 kg (5643.83 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 | Rear wheel drive |
| Number of gears and type of gearbox | 4 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, a 3.2-liter inline-six engine. This engine was a cornerstone of Mercedes-Benz’s mid-range offerings during the 1990s, known for its smoothness and reliability. The M104 featured a cast iron block with an aluminum cylinder head, incorporating dual overhead camshafts (DOHC) and four valves per cylinder. Fuel delivery was managed by a Bosch multi-port fuel injection system, optimizing combustion efficiency. 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 4G-TRONIC four-speed automatic transmission, a sophisticated unit for its time, offering smooth shifts and a focus on comfort. This transmission was electronically controlled, adapting shift points based on driving conditions and throttle input.
Driving Characteristics
The S 320 Automatic offered a distinctly comfortable and refined driving experience. While not as overtly sporty as the V8-powered S 420 or S 500, the inline-six provided ample power for effortless cruising and confident overtaking. The 4G-TRONIC transmission, while not offering the rapid shifts of modern gearboxes, prioritized smoothness and ease of use. Acceleration from 0 to 60 mph took approximately 8.5 seconds, and the car had a top speed of 139.81 mph. The automatic transmission’s gear ratios were tuned for relaxed highway driving, with a focus on maximizing fuel efficiency. Compared to the manual transmission options available on other S-Class models, the automatic S 320 traded some responsiveness for increased convenience.
Equipment & Trim Levels
The S 320 came standard with a comprehensive array of luxury features. Interior appointments included leather upholstery, wood trim, and power-adjustable front seats. Standard equipment also included automatic climate control, a premium sound system, and power windows and locks. Optional extras were plentiful, including a sunroof, upgraded sound systems, rear seat entertainment, and various driver assistance systems. The long-wheelbase configuration provided generous rear legroom, enhancing the comfort of passengers. The dashboard layout was typical of the V140 S-Class, featuring a clean and elegant design with intuitive controls.
Chassis & Braking
The V140 S-Class featured a robust chassis designed for both comfort and safety. The S 320 utilized a coil spring, double wishbone suspension at the front and an independent multi-link suspension at the rear, both incorporating a transverse stabilizer bar. This setup provided a smooth and controlled ride, even on uneven surfaces. 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 balanced feel and precise control.
Market Reception & Comparison
The S 320 was generally well-received by automotive critics. It was praised for its comfortable ride, refined engine, and luxurious interior. While some reviewers noted that the acceleration wasn’t as brisk as the V8 models, the S 320 was considered a sensible choice for buyers who prioritized comfort and fuel efficiency. Fuel economy was respectable for a luxury sedan of its size, averaging around 16.2 mpg in the city and 24.5 mpg on the highway. Compared to the S 280, the S 320 offered a noticeable performance upgrade, while the S 420 and S 500 provided even more power but at a higher price point and with increased fuel consumption.
Legacy
The M104 engine, found in the S 320, is known for its durability and longevity. Well-maintained examples can still provide reliable service today. The 4G-TRONIC transmission, while aging, is also generally robust, though it may require occasional servicing. In the used car market, the V140 S 320 represents a relatively affordable entry point into the world of Mercedes-Benz luxury. Its combination of comfort, refinement, and reliability has made it a popular choice among enthusiasts and collectors seeking a classic grand tourer. Parts availability remains good, ensuring that these cars can be kept on the road for years to come.
