For those in the market for a reliable and fuel-efficient diesel Mercedes Benz, the E320 CDI remains a compelling option, especially when equipped with the legendary OM648 inline-6 engine. While newer engines have emerged, the robust performance and simpler design of the OM648 continue to make models like the 2005-2006 E320 CDI highly sought after by enthusiasts and savvy buyers alike.
OM648 vs OM642: Understanding the Diesel Difference
Mercedes Benz offered two main diesel engine variants in the W211 E-Class: the OM648 and the OM642. The OM648 is a 3.2-liter inline-6, while the OM642 is a slightly smaller 3.0-liter V6. On paper, the OM642 might seem like the more modern choice with slightly higher horsepower and torque ratings. However, real-world driving experience and long-term ownership reveal a different story.
Many Mercedes technicians and owners favor the OM648 for its exceptional torque delivery that feels readily available across the rev range. It provides a smooth and effortless driving experience, particularly on highways where it achieves impressive fuel economy figures. The OM648 simply “goes,” as one experienced mechanic put it, offering a surge of power whenever needed. While the OM642 is also a capable engine, some find its power band to be narrower, requiring a bit more effort to find the sweet spot.
Reliability and Maintenance: The Edge Goes to the Inline-6
Beyond performance, the OM648 shines in terms of reliability and ease of maintenance. Its inline-6 configuration is inherently simpler than the V6 OM642. This translates to easier access to components for servicing and repairs. Owners and mechanics often describe the OM648 as “rock solid,” typical of inline engines known for their durability.
In contrast, the OM642, nestled in a V configuration, can be significantly more challenging and costly to work on. Accessing components can be cumbersome, requiring extensive disassembly. Reports indicate higher repair costs for the OM642, with common issues like oil leaks from the turbo Y-pipe and oil cooler adding to the expense. Even routine maintenance tasks can be more time-consuming and intricate on the OM642 compared to the straightforward OM648. For example, replacing components like the MAF sensor and EGR valve on an OM642 can be significantly more expensive due to the V engine’s dual components and complex layout.
Transmission Considerations: 5-Speed vs 7-Speed
When considering a Mercedes Benz E320 Cdi For Sale, it’s also important to note the transmission differences across model years. The 2005 and 2006 models typically came with a robust 5-speed automatic transmission, while later 2007-2009 models often featured a 7-speed transmission.
While the 7-speed offers more gears, some drivers prefer the more direct and responsive feel of the 5-speed, especially when paired with the OM648’s strong torque. The 5-speed transmission is known for its smooth and decisive shifts, contributing to the E320 CDI’s overall feeling of effortless power. Some find the 7-speed to be more prone to frequent shifting in search of the optimal gear, which can detract from the driving experience.
The Verdict: Seek Out the 2005-2006 Mercedes E320 CDI OM648
For those seeking a Mercedes Benz E320 CDI for sale, prioritizing models from 2005 and 2006 with the OM648 engine is a wise decision. These models offer a compelling combination of robust performance, proven reliability, easier maintenance, and a more engaging driving experience thanks to the powerful and straightforward OM648 inline-6 engine. While concerns about older Mercedes models and brake systems sometimes surface, focusing on well-maintained, lower mileage examples from the 2005-2006 production years provides a fantastic opportunity to own a truly exceptional diesel sedan.
