The 2008 Mercedes E320 Bluetec (W211) represents a significant step in diesel technology for the German automaker, offering a blend of luxury, performance, and fuel efficiency. For those considering a pre-owned E320 Bluetec, understanding its strengths and potential maintenance points is crucial. Having experience with both a 2008 E320 Bluetec and a newer 2013 E350 Bluetec (W212), I can offer some valuable insights into ownership and upkeep of the earlier model.
One of the well-known maintenance items for the first generation OM642 diesel engine, found in the 2008 Mercedes E320, is the oil cooler seals. It’s almost a certainty that these seals will need replacement at some point. However, this shouldn’t be a deterrent. Tackling the oil cooler seal replacement is a manageable DIY project for the competent home mechanic. Preparation is key – ensure you have the correct tools, including a good set of E-Torx sockets and the specific fuel injection line nut wrench. A copy of the Mercedes-Benz Workshop Information System (WIS) will also be invaluable. For parts, consider online retailers specializing in European car parts; many offer kits specifically for this job. These kits typically include all the necessary seals, a new swirl flap motor (essential for proper function), and a breather puck. While the cost might be around $600 for a comprehensive kit, doing this work yourself over a weekend can save significantly on labor costs.
Regarding emissions systems, it’s worth noting that the 2008 E320 Bluetec, unlike later models, does not use AdBlue or Diesel Exhaust Fluid (DEF). This simplifies maintenance and avoids potential issues associated with DEF systems. Also unique to the W211 diesel models is the inclusion of a donut spare tire, a space-saving solution. For those who prefer a full-size spare, it’s interesting to note that the older W210 generation Mercedes-Benz models were the last to feature this.
Moving to the chassis, the front suspension on any 2008 Mercedes E320 is now at least 15 years old and likely due for some attention. The W211 front suspension design is a departure from older Mercedes models like the W123, W124, W201, and W210, utilizing coil-over shocks instead of open coil springs. This design simplifies disassembly, often requiring just a floor jack to support the spindle while disconnecting ball joints. However, the ball joint design itself is less user-friendly than the W210’s two-legged ball joint. The 2008 E320 employs pressed-in ball joints, which can be more challenging to replace. If you are planning to keep your 2008 E320 in top condition, overhauling the front suspension is a worthwhile project.
The 2008 Mercedes E320 models are equipped with the 722.9 7-speed automatic transmission. A known potential weakness in this transmission is the VGS (Vehicle Transmission Control) unit, also known as the conductor plate. In the 722.9 transmission, the VGS unit integrates the transmission computer, unlike earlier 722.6 transmissions where the computer was separate. Replacing the VGS unit is not a straightforward DIY task because it requires SCN coding to your specific vehicle, a process typically done using dealer-level diagnostic tools like Xentry that can connect to Mercedes-Benz servers. The issue often arises from sensor failures on the VGS, leading to the car entering limp mode. While dealer replacement can be costly (around $1850 in one instance), more adventurous owners might explore replacing the sensors themselves after sourcing parts online and investing in specialized transmission fluid.
Even if your 2008 E320’s transmission seems fine, it’s a good preventative measure to have a Mercedes-Benz dealer read the transmission adaptations using Xentry. This provides insights into the transmission’s overall health. Furthermore, ensure the dealer applies the latest firmware updates to both the VGS and the Engine Control Unit (ECU). Early firmware versions had a known bug causing rough downshifts, especially when the transmission was cold, which is addressed by updated software. This firmware update service usually involves around an hour of shop time.
Engine lubrication is paramount for the longevity of the OM642 diesel engine in the 2008 E320 Bluetec. It is absolutely critical to use only Mercedes-Benz Sheet 229.52 specification oil, or its predecessors 228.51 or 229.51. Using incorrect engine oil can lead to damage to the diesel particulate filter (DPF). Mobil 1 ESP Formula 5W-30 is a commonly recommended oil that meets the MB 229.52 specification. Keep an eye out for sales at auto parts stores to potentially save on oil costs.
For in-car entertainment and electronics, most 2008 Mercedes E320 models came equipped with the Premium 1 Package, which included the COMAND system with navigation. While the navigation maps are dated, update discs can be found online at reasonable prices. Although the user interface might feel a bit clunky by modern standards, the navigation system is functional, and conveniently, it automatically sets the clock in the instrument cluster. Another feature to check for is the cell phone Bluetooth adapter stick, located in the center console in the rear. Originally designed for a specific Nokia phone, Mercedes-Benz later released a Bluetooth adapter that pairs with most Bluetooth-enabled phones for hands-free calling. However, this adapter typically supports only the Handsfree profile, not A2DP for music streaming. For audio streaming, later 2008 E320 models included a 1/8-inch auxiliary input jack in the glove box. Bluetooth audio streaming adapters that connect via the aux input are readily available for those wanting wireless music playback.
One significant improvement in the W211 generation compared to the preceding W210 is the addressed rust issue. Additionally, 2007-2009 W211 models, including the 2008 E320, feature traditional ABS brakes, replacing the Sensotronic Brake Control (SBC) system found in earlier W211s. This means these later models do not have the secondary motorcycle battery under the air filter, simplifying the electrical system with just the main battery in the trunk.
In conclusion, the 2008 Mercedes E320 Bluetec offers a compelling package of diesel efficiency and Mercedes-Benz luxury. While certain maintenance items are to be expected with age and mileage, particularly regarding oil cooler seals and potentially the transmission VGS unit, these are generally manageable. With proper care and attention to maintenance, the 2008 E320 Bluetec can continue to be a reliable and enjoyable vehicle.
