The Mercedes-Benz R-Class, specifically the W251 facelift model produced from 2010 to 2012, represented a unique offering in the luxury vehicle segment. The R 300 CDI V6 BlueEFFICIENCY, equipped with the 7G-TRONIC automatic transmission, was a diesel-powered variant aimed at providing a blend of space, efficiency, and comfort. Positioned as a mid-range option within the R-Class lineup, it slotted between the entry-level R 280 CDI and the more powerful R 350 CDI, appealing to buyers seeking a balance of performance and fuel economy in a large, versatile package. This model was primarily marketed in Europe and other regions where diesel engines were favored, though it saw limited sales in the United States.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | R-class |
| Generation | R-class (W251, facelift 2010) |
| Type (Engine) | R 300 CDI V6 BlueEFFICIENCY (190 Hp) G-TRONIC |
| Start of production | 2010 |
| End of production | 2012 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Station wagon (estate) |
| Seats | 5 |
| Doors | 5 |
| Fuel consumption (combined) | 7.6 l/100 km (30.9 US mpg, 37.2 UK mpg, 13.2 km/l) |
| CO2 emissions | 199 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 9.5 sec |
| Acceleration 0 – 62 mph | 9.5 sec |
| Acceleration 0 – 60 mph | 9 sec |
| Maximum speed | 215 km/h (133.59 mph) |
| Emission standard | Euro 5 |
| Weight-to-power ratio | 11.5 kg/Hp, 87 Hp/tonne |
| Weight-to-torque ratio | 5 kg/Nm, 201.4 Nm/tonne |
| Power | 190 Hp @ 3800 rpm |
| Power per litre | 63.6 Hp/l |
| Torque | 440 Nm @ 1400-2800 rpm (324.53 lb.-ft. @ 1400-2800 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | OM 642.870 |
| Engine displacement | 2987 cm3 (182.28 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | V-engine |
| Compression ratio | 15.5:1 |
| 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 | 2185 kg (4817.1 lbs.) |
| Max. weight | 2840 kg (6261.13 lbs.) |
| Max load | 655 kg (1444.03 lbs.) |
| Trunk (boot) space – minimum | 550 l (19.42 cu. ft.) |
| Trunk (boot) space – maximum | 1950 l (68.86 cu. ft.) |
| Fuel tank capacity | 80 l (21.13 US gal | 17.6 UK gal) |
| Permitted trailer load with brakes (12%) | 2100 kg (4629.71 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Length | 4922 mm (193.78 in.) |
| Width | 1922 mm (75.67 in.) |
| Height | 1674 mm (65.91 in.) |
| Wheelbase | 2980 mm (117.32 in.) |
| Front track | 1661 mm (65.39 in.) |
| Rear (Back) track | 1651 mm (65 in.) |
| Minimum turning circle | 12 m (39.37 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| 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 | Ventilated discs |
| 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 | 17 |
Powertrain & Engine Architecture
The heart of the R 300 CDI BlueEFFICIENCY is the OM 642.870 3.0-liter V6 diesel engine. This engine is a member of the OM642 family, known for its robust construction and relatively smooth operation for a diesel. The “BlueEFFICIENCY” designation indicates the inclusion of technologies aimed at improving fuel economy and reducing emissions, such as optimized combustion chamber geometry and a more efficient turbocharger. The engine utilizes a common rail direct injection system, delivering fuel at extremely high pressures for improved atomization and combustion. A variable geometry turbocharger (VGT) with an intercooler further enhances performance and efficiency. The 7G-TRONIC automatic transmission, a seven-speed unit, was standard. This transmission is known for its smooth shifts and wide gear ratio spread, contributing to both fuel economy and drivability.
Driving Characteristics
The R 300 CDI Automatic offered a comfortable and relaxed driving experience. With 190 horsepower and 440 Nm (324 lb-ft) of torque, acceleration was adequate for highway cruising and overtaking, though not particularly sporty. The 0-60 mph time of around 9 seconds reflects this. The 7G-TRONIC transmission played a crucial role in maximizing the engine’s output, providing smooth and timely gear changes. Compared to the more powerful R 350 CDI, the R 300 CDI felt less urgent in its acceleration. However, it offered significantly better fuel economy. The automatic transmission, while convenient, did result in a slight loss of responsiveness compared to the available manual transmission options in other R-Class variants.
Equipment & Trim Levels
The R 300 CDI BlueEFFICIENCY typically came well-equipped, reflecting its luxury positioning. Standard features included automatic climate control, power-adjustable front seats, a multi-function steering wheel, and an audio system with CD player. Leather upholstery was often standard, or available as an option. Optional extras included a navigation system, premium sound system, sunroof, and parking sensors. The interior design was typical of Mercedes-Benz at the time, emphasizing quality materials and a refined aesthetic. The R-Class was notable for its available third-row seating, offering seating for up to seven passengers, though this option reduced cargo space.
Chassis & Braking
The R-Class featured a robust chassis designed to handle the vehicle’s weight and provide a comfortable ride. The front suspension utilized a double wishbone setup, while the rear employed an independent multi-link spring suspension with a stabilizer bar. This configuration aimed to balance ride comfort with handling stability. The braking system consisted of ventilated discs at the front and solid discs at the rear, coupled with ABS (Anti-lock Braking System). The R 300 CDI’s weight (approximately 2185 kg or 4817 lbs) meant that the braking system needed to be effective to provide confident stopping power.
Market Reception & Comparison
The Mercedes-Benz R-Class, in general, received mixed reviews. Critics often praised its spacious interior and comfortable ride, but questioned its styling, which was considered somewhat awkward by some. The R 300 CDI specifically was lauded for its fuel efficiency and smooth powertrain. Compared to the R 350 CDI, it offered a more economical option without sacrificing too much in terms of comfort. However, it lacked the outright performance of its more powerful sibling. Against competitors like the BMW X5 and Audi Q7, the R-Class offered a unique blend of station wagon practicality and luxury features, but struggled to gain significant market share.
Legacy
The OM 642 engine family, including the OM 642.870 found in the R 300 CDI, has proven to be remarkably durable and reliable. With proper maintenance, these engines can accumulate high mileage without major issues. The 7G-TRONIC transmission is also generally considered reliable, though fluid changes are crucial for longevity. In the used car market, the R 300 CDI BlueEFFICIENCY represents a relatively affordable entry point into the Mercedes-Benz luxury segment. Its fuel efficiency and spacious interior continue to appeal to buyers seeking a practical and comfortable vehicle. However, potential buyers should be aware of the potential for higher maintenance costs associated with a complex European vehicle.
