2010-2013 Mercedes-Benz S-class (W221 facelift ) S 350 CDI BlueTEC (258 Hp) G-TRONIC

The Mercedes-Benz S 350 CDI BlueTEC, produced from 2010 to 2013, was a diesel-powered variant of the W221 S-Class following the 2009 facelift. Positioned as a mid-range offering within the S-Class lineup, it aimed to provide a balance between luxury, performance, and fuel efficiency. This model represented a significant step in Mercedes-Benz’s efforts to combine powerful diesel engines with advanced emissions control technology, specifically the BlueTEC system, to meet increasingly stringent environmental regulations. The W221 generation S-Class, built on the 1HX0/A3 platform, was known for its technological innovations and opulent interior, and the S 350 CDI BlueTEC continued this tradition while offering a more economical alternative to the gasoline-powered models.

Powertrain & Engine Architecture

The heart of the S 350 CDI BlueTEC is the OM 642.862 3.0-liter V6 diesel engine. This engine is a longitudinal, turbocharged and intercooled design, producing 258 horsepower at 3600 rpm and a substantial 620 Nm (457.29 lb-ft) of torque between 1600 and 2400 rpm. The engine features a high compression ratio of 15.5:1 and utilizes a common rail direct fuel injection system, enabling precise fuel delivery and optimized combustion. The turbocharger, coupled with an intercooler, enhances power output and efficiency. The BlueTEC system, a key component of this engine, incorporates a selective catalytic reduction (SCR) system utilizing AdBlue (diesel exhaust fluid) to significantly reduce nitrogen oxide (NOx) emissions. This allowed the S 350 CDI BlueTEC to meet Euro 6 emission standards.

Paired with the OM 642.862 engine is the 7G-TRONIC seven-speed automatic transmission. This transmission is renowned for its smooth shifting and responsiveness. The 7G-TRONIC utilizes a torque converter and planetary gearsets, offering a wide range of gear ratios to optimize both fuel economy and performance. The transmission’s electronic control unit adapts shift points based on driving conditions and driver input, contributing to a refined driving experience. Unlike some competitors, Mercedes-Benz did not offer a manual transmission option for this specific S-Class variant.

Engine Specifications

The OM 642.862 engine is constructed with an aluminum cylinder head and a cast iron engine block, providing a robust and durable foundation. The engine employs four valves per cylinder, enhancing volumetric efficiency and contributing to its power output. The engine oil capacity is 8 liters (8.45 US qt / 7.04 UK qt), and the coolant capacity is also 8 liters. A particulate filter is included as standard equipment to further reduce emissions.

Driving Characteristics

The S 350 CDI BlueTEC delivers a distinctly different driving experience compared to the higher-powered S-Class models like the S 550. While not as overtly sporty, the abundant torque from the diesel engine provides strong acceleration, particularly in the mid-range. The 0-100 km/h (0-62 mph) acceleration time of 7.1 seconds is respectable for a large luxury sedan. The 7G-TRONIC transmission contributes to smooth and seamless gear changes, enhancing the overall driving comfort. The gear ratios are tuned to prioritize fuel efficiency at cruising speeds, while still providing ample power for overtaking maneuvers. Compared to the gasoline-powered S-Class variants, the S 350 CDI BlueTEC offers superior fuel economy without sacrificing a significant amount of performance. The diesel engine’s torque curve also makes it well-suited for effortless highway cruising and towing, although the S-Class was not typically used for heavy towing.

Equipment & Trim Levels

The S 350 CDI BlueTEC came standard with a comprehensive array of luxury features, befitting its S-Class designation. Standard equipment typically included leather upholstery, power-adjustable front seats with memory function, dual-zone automatic climate control, a premium audio system, and a navigation system. Safety features were also abundant, including ABS, electronic stability control, multiple airbags, and parking sensors. Optional extras included features such as a panoramic sunroof, rear seat entertainment system, massaging seats, and advanced driver-assistance systems like Distronic Plus adaptive cruise control and lane-keeping assist. Interior trim options included various wood veneers and aluminum accents, allowing buyers to personalize the cabin to their preferences. The dashboard configuration was consistent across the W221 facelift models, featuring a prominent central display screen and a sophisticated instrument cluster.

Chassis & Braking

The S 350 CDI BlueTEC utilizes a fully independent suspension system, featuring air suspension with Adaptive Damping System (ADS) as standard. This system automatically adjusts the damping characteristics based on road conditions and driving style, providing a comfortable and controlled ride. The front suspension employs a multi-link design, while the rear suspension utilizes a multi-link setup with air springs. The vehicle is equipped with disc brakes on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) and Electronic Stability Program (ESP) are standard safety features. The S 350 CDI BlueTEC’s curb weight of 1920 kg (4232.88 lbs) is relatively high, but the suspension system effectively manages the vehicle’s mass, delivering a composed and stable driving experience. Tire size is typically 235/55 R17, mounted on 17-inch alloy wheels.

Market Reception & Comparison

The S 350 CDI BlueTEC was generally well-received by automotive critics. It was praised for its fuel efficiency, comfortable ride, and refined interior. While some reviewers noted that it lacked the outright performance of the gasoline-powered S-Class models, the majority acknowledged that the diesel engine provided ample power for most driving situations. Compared to the S 550, the S 350 CDI BlueTEC offered significantly better fuel economy – achieving combined fuel consumption of 6.8-6.9 l/100 km (34.6-34.1 US mpg) – at a lower price point. The S 350 CDI BlueTEC also offered a more economical alternative to the S 400 Hybrid. Reliability was generally good, although the complex BlueTEC emissions system required careful maintenance to ensure optimal performance and longevity. The diesel particulate filter and SCR system required periodic servicing and the use of AdBlue fluid.

Technical Specifications

Legacy

The S 350 CDI BlueTEC represents a significant milestone in Mercedes-Benz’s diesel engine technology. The OM 642.862 engine, coupled with the BlueTEC emissions system, demonstrated the potential for combining diesel power with environmental responsibility. While diesel engines have faced increasing scrutiny in recent years, the OM 642 engine family is generally regarded as durable and reliable, provided it receives regular maintenance. On the used car market, the S 350 CDI BlueTEC remains a popular choice for buyers seeking a luxurious and fuel-efficient sedan. However, potential buyers should be aware of the maintenance requirements of the BlueTEC system, including the need for AdBlue refills and periodic servicing of the particulate filter and SCR catalyst. The S 350 CDI BlueTEC’s blend of luxury, performance, and efficiency has cemented its place as a desirable and well-regarded variant within the W221 S-Class generation.