The 2008 Mercedes E320 Bluetec represents a significant step in diesel technology, offering a blend of luxury and fuel efficiency. This guide provides insights into common ownership experiences, potential issues, and maintenance considerations for this model. Drawing from firsthand experience with both the first-generation (W211) and second-generation (W212) OM642 diesel engines, we aim to offer a comprehensive overview.
Common Issues and Maintenance for the 2008 E320 Bluetec
Oil Cooler Seals: A frequent issue in the first-generation OM642 engine found in the 2008 E320 Bluetec is oil cooler seal failure. While not catastrophic, this repair requires specialized tools, including E-Torx sockets and a fuel injection line nut wrench. A comprehensive online kit containing all necessary seals, a new swirl flap motor (crucial for proper function), and a breather puck is recommended. With the right tools and preparation, this repair can be tackled over a long weekend.
Front Suspension: Given the age of the W211 chassis, front suspension work is often necessary. Unlike older Mercedes models, the W211 utilizes coil-over shocks, simplifying disassembly with a standard floor jack. However, the pressed-in ball joints can present a challenge during replacement.
722.9 Transmission: The 722.9 transmission in the 2008 E320 Bluetec has a known weakness: the Valve Gearbox Sensor (VGS), also known as the conductor plate. This unit integrates the transmission computer and requires specialized dealer-level software (Xentry) for replacement and SCN coding. Sensor failures within the VGS can trigger limp mode. While DIY sensor replacement is possible, professional VGS replacement and coding are generally recommended.
Preventative Maintenance: Transmission Software Updates Even with a functioning VGS, a dealer visit to read transmission adaptations and apply the latest firmware updates is advisable. Firmware updates address known issues like rough downshifts, particularly when cold.
Engine Oil: Using the correct engine oil is paramount for the 2008 E320 Bluetec. Mercedes-Benz specifies MB Sheet 229.52 oil (or predecessors 228.51 or 229.51) to protect the diesel particulate filter (DPF). Mobil 1 ESP is the recommended oil meeting this specification.
Audio and Electronics: COMAND Navigation System Most 2008 E320 Bluetecs feature the COMAND navigation system. While map updates are no longer available from Mercedes-Benz, aftermarket update discs can be found. The system also includes Bluetooth functionality, primarily for hands-free calling. Later models may include an auxiliary input jack in the glove box, allowing for connection to external audio sources. Adapting the system for A2DP music streaming via Bluetooth often involves using aftermarket adapters and some wiring modifications.
Rust and Brakes: The W211 generation addressed the rust issues that plagued the previous W210 models. The 2007-2009 models also feature a traditional ABS braking system, eliminating the need for the secondary battery found in earlier models equipped with the Sensotronic Brake Control (SBC) system.
Conclusion: Owning a 2008 Mercedes E320 Bluetec
The 2008 Mercedes E320 Bluetec offers a unique driving experience, combining diesel efficiency with luxury and comfort. Awareness of potential issues like oil cooler seals and the 722.9 transmission’s VGS is essential. Proactive maintenance, including using the correct engine oil and keeping the transmission software updated, is crucial for long-term reliability and enjoyment. While some repairs may require specialized tools or dealer intervention, many owners find the E320 Bluetec to be a rewarding vehicle to own and maintain.
