The Mercedes-Benz S-Class Long (V221) S 320 CDI 7G-TRONIC, produced from 2006 to 2009, represented a compelling blend of luxury, performance, and efficiency within the flagship S-Class range. This long-wheelbase variant, specifically equipped with the OM642.930 3.0-liter turbocharged diesel engine and the 7G-TRONIC seven-speed automatic transmission, was primarily aimed at markets where larger, chauffeur-driven luxury sedans were highly valued. It occupied a middle ground in the V221 lineup, offering a significant step up in refinement and power compared to the base S 320 models, while remaining more accessible than the high-performance S 500 or S 600 variants.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | S-Class |
| Generation | S-Class Long (V221) |
| Type (Engine) | S 320 CDI (235 Hp) 7G-TRONIC |
| Start of production | 2006 |
| End of production | 2009 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 11.7-11.9 l/100 km (20.1 – 19.8 US mpg) |
| Fuel consumption (extra urban) | 6.5-6.7 l/100 km (36.2 – 35.1 US mpg) |
| Fuel consumption (combined) | 8.4-8.6 l/100 km (28 – 27.4 US mpg) |
| CO2 emissions | 223-228 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 7.8 sec |
| Acceleration 0 – 62 mph | 7.8 sec |
| Acceleration 0 – 60 mph | 7.4 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Weight-to-power ratio | 8.2 kg/Hp |
| Weight-to-torque ratio | 3.6 kg/Nm |
| Power | 235 Hp @ 3600 rpm |
| Torque | 540 Nm @ 1600 rpm (398.28 lb.-ft. @ 1600 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | OM 642.930 |
| Engine displacement | 2987 cm3 (182.28 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | V-engine |
| Cylinder Bore | 83 mm (3.27 in.) |
| Piston Stroke | 92 mm (3.62 in.) |
| Compression ratio | 18:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 8.5 l (8.98 US qt | 7.48 UK qt) |
| Coolant | 7.5 l (7.93 US qt | 6.6 UK qt) |
| Kerb Weight | 1925 kg (4243.9 lbs.) |
| Max. weight | 2580 kg (5687.93 lbs.) |
| Max load | 655 kg (1444.03 lbs.) |
| Trunk (boot) space – minimum | 560 l (19.78 cu. ft.) |
| Fuel tank capacity | 90 l (23.78 US gal | 19.8 UK gal) |
| Length | 5209 mm (205.08 in.) |
| Width | 1872 mm (73.7 in.) |
| Height | 1473 mm (57.99 in.) |
| Wheelbase | 3165 mm (124.61 in.) |
| Front track | 1604 mm (63.15 in.) |
| Rear (Back) track | 1606 mm (63.23 in.) |
| Front overhang | 871 mm (34.29 in.) |
| Rear overhang | 1173 mm (46.18 in.) |
| Minimum turning circle | 12.2 m (40.03 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| Drive wheel | Rear wheel drive |
| Number of gears | 7 |
| Gearbox type | Automatic transmission G-TRONIC |
| Front suspension | Air suspension |
| Rear suspension | Air suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Tires size | 235/55 R17 |
| Wheel rims size | 8J x 17 |
Powertrain & Engine Architecture
The heart of the S 320 CDI was the OM642.930 3.0-liter V6 diesel engine. This engine was a significant advancement in Mercedes-Benz’s diesel technology, featuring common-rail direct injection, a variable geometry turbocharger, and an intercooler. The common-rail system, operating at extremely high pressures, allowed for precise fuel metering and optimized combustion, resulting in improved power and reduced emissions. The V6 configuration provided inherent smoothness, while the turbocharger boosted power output to 235 horsepower and a substantial 540 Nm (398 lb-ft) of torque. The 7G-TRONIC seven-speed automatic transmission was a key component, offering smooth and efficient gear changes. It featured a torque converter lock-up clutch that engaged in most gears, improving fuel economy and reducing slippage. The transmission was electronically controlled and adapted to the driver’s style and driving conditions.
Driving Characteristics
The S 320 CDI Long offered a refined and comfortable driving experience. While not as overtly sporty as some of its gasoline-powered siblings, the diesel engine delivered ample torque from low engine speeds, providing effortless acceleration in most driving situations. The 7G-TRONIC transmission contributed to this smoothness, seamlessly shifting gears and keeping the engine in its optimal power band. The long wheelbase provided a supremely comfortable ride, absorbing bumps and imperfections in the road with ease. Compared to the S 320 with the naturally aspirated gasoline engine, the CDI version offered significantly more torque and better fuel economy. It wasn’t as quick as the S 500, but the difference in everyday driving was often less noticeable than the substantial price gap.
Equipment & Trim Levels
The S 320 CDI Long came standard with a comprehensive array of luxury features, befitting its flagship status. These included leather upholstery, wood trim, automatic climate control, a premium sound system, and power-adjustable seats with memory function. Common options included a sunroof, rear seat entertainment system, massaging seats, and advanced driver-assistance systems like Distronic adaptive cruise control and Parktronic parking assist. The long wheelbase provided increased rear legroom, making it particularly appealing to passengers who prioritized comfort. Interior color schemes were customizable, allowing buyers to personalize their vehicles.
Chassis & Braking
The V221 S-Class featured an advanced chassis design, incorporating an air suspension system on both the front and rear axles. This air suspension provided a remarkably smooth ride and allowed the vehicle to automatically adjust its ride height based on speed and load. The S 320 CDI Long was equipped with ventilated disc brakes on all four wheels, providing ample stopping power. An Anti-lock Braking System (ABS) was standard, enhancing safety and stability during emergency braking maneuvers. The steering system utilized a rack-and-pinion design, offering precise and responsive handling.
Market Reception & Comparison
The S 320 CDI Long was generally well-received by automotive critics. It was praised for its comfortable ride, refined interior, and impressive fuel economy for a vehicle of its size and luxury. The diesel engine was noted for its quiet operation and abundant torque. Compared to the gasoline-powered S 320, the CDI version offered a better balance of performance and efficiency. However, some critics noted that the diesel engine lacked the responsiveness and refinement of the higher-end gasoline engines. In terms of reliability, the OM642 engine proved to be generally robust, although some owners reported issues with the diesel particulate filter (DPF) and glow plugs.
Legacy
The Mercedes-Benz S-Class Long (V221) S 320 CDI 7G-TRONIC remains a desirable used car today, particularly for those seeking a luxurious and comfortable long-distance cruiser. The OM642 engine, while requiring diligent maintenance (especially regarding the DPF system), is known for its longevity. Parts availability is generally good, and the vehicle’s sophisticated technology continues to impress. The S 320 CDI Long represents a sweet spot in the V221 lineup, offering a compelling combination of luxury, performance, and efficiency at a relatively affordable price point in the used car market.
