2009-2011 Mercedes-Benz C-class (W204) C 350 CDI BlueEFFICIENCY V6 (231 Hp) 7G-TRONIC

The Mercedes-Benz C 350 CDI BlueEFFICIENCY, produced between 2009 and 2011, was a key variant within the W204 C-Class range. Positioned as a mid-to-upper trim level, it offered a compelling blend of performance and fuel efficiency thanks to its advanced diesel technology. This model represented Mercedes-Benz’s commitment to delivering refined luxury with reduced emissions, appealing to buyers seeking a sophisticated and economical executive sedan. It was primarily marketed in Europe and other regions where diesel engines held significant market share, offering a premium alternative to gasoline-powered C-Class models.

Technical Specifications

INTRODUCTION

The C 350 CDI BlueEFFICIENCY, launched in 2009 as part of the W204 C-Class facelift, represented a significant upgrade in diesel performance and efficiency for Mercedes-Benz. Built on the 1HX0/A3 platform, this variant aimed to bridge the gap between the more affordable C 220 CDI and the higher-performance C 63 AMG. It was designed to appeal to drivers who desired a luxurious and refined driving experience without sacrificing fuel economy or torque. The “BlueEFFICIENCY” designation signified the implementation of various technologies aimed at reducing emissions and improving overall efficiency.

Powertrain & Engine Architecture

At the heart of the C 350 CDI BlueEFFICIENCY lies the OM 642.830 3.0-liter V6 diesel engine. This engine is a robust and sophisticated 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. The engine is turbocharged with a variable geometry turbocharger (VGT) and intercooled, enhancing both power and torque across a wide RPM range. The valvetrain employs double overhead camshafts (DOHC) with four valves per cylinder, contributing to efficient gas exchange. Paired with the engine is the 7G-TRONIC seven-speed automatic transmission, known for its smooth shifting and responsiveness. This transmission features a torque converter lock-up clutch to improve efficiency at cruising speeds. The 7G-TRONIC also offered a manual shift mode for drivers who preferred more control.

Driving Characteristics

The C 350 CDI BlueEFFICIENCY offered a distinctly different driving experience compared to its siblings. The 231 horsepower and 540 Nm (398 lb-ft) of torque provided ample power for both relaxed cruising and spirited acceleration. The 7G-TRONIC transmission was well-matched to the engine’s characteristics, providing smooth and quick gear changes. While not as overtly sporty as the C 350 gasoline variant, the CDI offered a more relaxed and refined driving experience, with a strong emphasis on low-end torque. This made it particularly well-suited for highway driving and overtaking maneuvers. Compared to the C 220 CDI, the C 350 CDI offered significantly more power and a more responsive feel. The gear ratios in the 7G-TRONIC were optimized for both fuel efficiency and performance, allowing the engine to operate within its peak torque band for extended periods.

Equipment & Trim Levels

The C 350 CDI BlueEFFICIENCY typically came well-equipped as a mid-to-upper trim level. Standard features often included leather upholstery, automatic climate control, a multi-function steering wheel, and a high-end audio system. Optional extras included a sunroof, navigation system, parking sensors, and upgraded interior trim options. The interior design was typical of Mercedes-Benz, emphasizing luxury and comfort. The dashboard layout was clean and functional, with a focus on ergonomics. The BlueEFFICIENCY models often featured unique badging and trim details to distinguish them from other C-Class variants.

Chassis & Braking

The W204 C-Class featured a sophisticated chassis design, with an independent McPherson strut suspension at the front and a multi-link suspension at the rear. The C 350 CDI BlueEFFICIENCY benefited from a slightly stiffer suspension setup compared to the lower-trim models, providing improved handling and stability. Braking duties were handled by ventilated discs at the front and solid discs at the rear, equipped with ABS (Anti-lock Braking System) and electronic brake-force distribution. The steering system was a rack-and-pinion setup with hydraulic power assistance, offering precise and responsive steering feel.

Market Reception & Comparison

The C 350 CDI BlueEFFICIENCY was generally well-received by automotive critics. It was praised for its refined driving experience, strong performance, and excellent fuel economy. Compared to the C 350 gasoline variant, the CDI offered superior fuel efficiency and torque, making it a more practical choice for many buyers. However, some critics noted that the diesel engine was slightly noisier than the gasoline engine. In terms of reliability, the OM 642 engine proved to be a durable and long-lasting design, although regular maintenance was essential to ensure optimal performance. Fuel economy figures consistently demonstrated the C 350 CDI’s efficiency, making it a cost-effective option for high-mileage drivers.

Legacy

The C 350 CDI BlueEFFICIENCY remains a popular choice in the used car market today. Its combination of luxury, performance, and fuel efficiency continues to appeal to buyers seeking a well-rounded executive sedan. The OM 642 engine is known for its longevity and relatively low maintenance costs, provided it is properly maintained. While modern diesel technology has advanced significantly, the C 350 CDI BlueEFFICIENCY represents a high point in Mercedes-Benz’s diesel engine development, offering a refined and capable driving experience that still holds up well today. Finding well-maintained examples is key, as with any used vehicle, but the C 350 CDI BlueEFFICIENCY offers a compelling blend of value and sophistication.