The Mercedes-Benz R-Class Long (V251) R 350 CDI V6 4MATIC G-TRONIC, produced from 2009 to 2010, represented a unique offering in the luxury vehicle segment. Positioned as a spacious, six or seven-passenger vehicle, the R-Class aimed to blend the practicality of a minivan with the prestige and driving experience associated with Mercedes-Benz. The “Long” designation indicated an extended wheelbase version, primarily sold in European and select international markets, offering increased rear passenger legroom and cargo capacity. This particular R 350 CDI variant occupied a mid-to-upper position within the R-Class lineup, offering a balance of performance, fuel efficiency, and luxury features. It was designed to appeal to buyers needing a versatile vehicle for family transport or active lifestyles, without sacrificing the Mercedes-Benz brand experience.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | R-Class |
| Generation | R-Class Long (V251) |
| Type (Engine) | R 350 CDI V6 (224 Hp) 4MATIC G-TRONIC |
| Start of production | 2009 |
| End of production | 2010 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Station wagon (estate) |
| Seats | 5-7 |
| Doors | 5 |
| Fuel consumption (combined) | 9.3 l/100 km (25.3 US mpg, 30.4 UK mpg, 10.8 km/l) |
| CO2 emissions | 246 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 8.8 sec |
| Acceleration 0 – 62 mph | 8.8 sec |
| Acceleration 0 – 60 mph | 8.4 sec |
| Maximum speed | 222 km/h (137.94 mph) |
| Emission standard | Euro 5 |
| Weight-to-power ratio | 10.2 kg/Hp, 97.6 Hp/tonne |
| Weight-to-torque ratio | 4.5 kg/Nm, 222.2 Nm/tonne |
| Power | 224 Hp |
| Power per litre | 75 Hp/l |
| Torque | 510 Nm (376.16 lb.-ft.) |
| Maximum engine speed | 4500 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | OM 642.950 |
| 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 | 16.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 8.5 l (8.98 US qt | 7.48 UK qt) |
| Coolant | 10.1 l (10.67 US qt | 8.89 UK qt) |
| Kerb Weight | 2295 kg (5059.61 lbs.) |
| Max. weight | 2895 kg (6382.38 lbs.) |
| Max load | 600 kg (1322.77 lbs.) |
| Trunk (boot) space – maximum | 2385 l (84.23 cu. ft.) |
| Fuel tank capacity | 80 l (21.13 US gal | 17.6 UK gal) |
| Max. roof load | 100 kg (220.46 lbs.) |
| Permitted trailer load with brakes (12%) | 2100 kg (4629.71 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Length | 5157 mm (203.03 in.) |
| Width | 1922 mm (75.67 in.) |
| Height | 1659 mm (65.31 in.) |
| Wheelbase | 3215 mm (126.57 in.) |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 7 gears, automatic transmission G-TRONIC |
| Front suspension | Double wishbone |
| Rear suspension | Independent multi-link spring suspension with stabilizer |
| Front brakes | Disc |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Hydraulic Steering |
| Tires size | 235/65 R17 |
| Wheel rims size | 7.5J x 17 |
Powertrain & Engine Architecture
The R 350 CDI is powered by the OM 642.950 3.0-liter V6 diesel engine. This engine is a robust and well-regarded design, featuring a cast iron block and aluminum cylinder heads. It utilizes a common rail direct injection system, delivering fuel at extremely high pressures for optimized combustion. A variable geometry turbocharger with an intercooler further enhances performance and efficiency. The engine produces 224 horsepower and a substantial 510 Nm (376 lb-ft) of torque. The G-TRONIC automatic transmission, a 7-speed unit, was specifically tuned to handle the engine’s torque output and provide smooth, responsive shifts. This transmission offered a manual shift mode for greater driver control. The engine’s longitudinal mounting and all-wheel-drive system (4MATIC) contributed to balanced handling and traction.
Driving Characteristics
The R 350 CDI offered a comfortable and refined driving experience. The 7-speed automatic transmission, while not particularly sporty, provided smooth gear changes and helped to keep the engine in its optimal power band. Acceleration to 60 mph took approximately 8.4 seconds, which was adequate for a vehicle of this size and weight. The abundant torque made overtaking maneuvers relatively effortless. Compared to the gasoline-powered R 350, the CDI version offered significantly better fuel economy and a more relaxed cruising experience. The 4MATIC all-wheel-drive system provided enhanced stability and traction, particularly in inclement weather. However, the R-Class’s size and weight meant it wasn’t as agile or engaging to drive as smaller, sportier vehicles.
Equipment & Trim Levels
The R 350 CDI Long typically came well-equipped with standard features including leather upholstery, dual-zone automatic climate control, a premium audio system, and power-adjustable front seats. Optional extras included a rear entertainment system, panoramic sunroof, navigation system, and advanced driver-assistance features like Distronic adaptive cruise control. Interior trim options varied, allowing buyers to customize the cabin to their preferences. The extended wheelbase version prioritized rear passenger comfort, offering ample legroom and available features like individual climate control and reclining seats.
Chassis & Braking
The R-Class Long featured a double wishbone front suspension and an independent multi-link rear suspension, both incorporating stabilizer bars to reduce body roll. This setup provided a comfortable ride quality, absorbing bumps and imperfections in the road surface effectively. The vehicle was equipped with disc brakes on all four wheels, coupled with an Anti-lock Braking System (ABS) for enhanced stopping power and control. The steering was hydraulic power-assisted, providing a reasonably direct and responsive feel.
Market Reception & Comparison
The Mercedes-Benz R-Class, despite its innovative concept, struggled to gain widespread acceptance in the market. Critics often pointed to its somewhat awkward styling and its positioning as being difficult to define – it wasn’t quite a traditional SUV, minivan, or wagon. The R 350 CDI, however, was generally praised for its fuel efficiency and strong torque output. Compared to the R 350 gasoline variant, the CDI offered superior fuel economy and a more relaxed driving experience. Against competitors like the Acura MDX or BMW X5, the R-Class offered a unique combination of space, luxury, and diesel efficiency, but its unconventional design limited its appeal.
Legacy
The OM 642 engine family, including the OM 642.950 found in the R 350 CDI, is known for its durability and reliability. With proper maintenance, these engines can accumulate high mileage. The G-TRONIC transmission is also generally considered to be a robust unit. However, like any complex vehicle, the R-Class can be prone to age-related issues, such as air suspension problems and electronic component failures. On the used car market, the R 350 CDI represents a relatively affordable entry point into the Mercedes-Benz luxury segment, offering a spacious and comfortable vehicle with good fuel economy. Its unique design and limited production numbers have also given it a degree of cult following among enthusiasts.
