For owners and enthusiasts of the 2005 Mercedes E Class E320, a crucial point of consideration often revolves around the engine choice: the inline-6 cylinder 648 engine or the later V6 cylinder 642 engine. Both offer a distinct driving experience, but when it comes to long-term reliability and ease of maintenance, opinions diverge. This article delves into a comparison, particularly favoring the simpler and arguably more robust inline-6 variant for the 2005 E320.
The Merits of the 648 Inline-6 Engine in the 2005 E320
The 648 engine, an inline-6 diesel, is often lauded for its straightforward design and well-understood mechanics. This simplicity translates to easier maintenance and repair procedures. Tasks such as replacing the alternator or addressing oil cooler seals are notably less complicated compared to its V6 counterpart. Furthermore, the 648 engine in the 2005 Mercedes E Class E320 is paired with the 722.6 5-speed transmission, a gearbox renowned for its robustness. Issues with this transmission are typically resolvable, often by replacing the conductor plate – a task described as messy but fundamentally uncomplicated. Even limp mode, a common concern, can frequently be attributed to connector leaks, a minor and inexpensive fix involving a $15 part and some electronic parts cleaner to address ATF flooding of the TCM.
One acknowledged issue with the 648 is “black death,” characterized by tar accumulation under the valve cover. While cleaning this is labor-intensive and requires fuel line connector replacements, it is not generally considered a terminal problem for the engine’s lifespan. Another point to consider for the 2005 Mercedes E Class E320 with the 648 engine is the glow plugs. Ensuring these have been replaced recently or regularly is advisable, as a broken glow plug during removal can necessitate cylinder head removal, a significantly more involved repair.
The 642 V6 Engine: Refinement and Complexity
In contrast, the 642 V6 engine, while offering a more refined driving experience, introduces increased complexity. Coupled with the 722.9 7-speed transmission, also generally robust, it presents its own set of challenges. Conductor plate failure in the 722.9 transmission, while also a potential issue, becomes more intricate due to the TCM being SCN coded and integral to the conductor plate. Replacing this component often requires dealer-level equipment for coding, as aftermarket solutions may not suffice. While specialized shops can repair conductor plates, maintaining the original unit married to the car, it highlights a layer of complexity absent in the 722.6. Moreover, the 722.9 transmission lacks a dipstick tube, requiring pressurized fluid for filling, which can complicate even minor leak management. Additionally, the original text suggests that environmental technologies in the 642, while beneficial for emissions, might introduce further complexities to engine maintenance compared to the 648.
Investing in Diagnostic Tools
Regardless of the engine choice in a 2005 Mercedes E Class E320, investing in a capable code scanner is a prudent recommendation. A scanner capable of reading and clearing more than just powertrain codes, ranging in price from $60-$750, can be invaluable for both engine types. Options extend from Bluetooth dongles to more comprehensive standalone systems, albeit with a learning curve to effectively utilize their full capabilities.
Conclusion: Simplicity and Maintainability in the 2005 E320
In conclusion, for the 2005 Mercedes E Class E320, the 648 inline-6 engine presents a compelling case for those prioritizing simplicity and maintainability. While the 642 V6 offers refinement, the 648’s straightforward design and the robustness of its paired 722.6 transmission make it an attractive option for owners concerned with ease of repair and long-term reliability. The simpler nature of the 648 engine, in the context of a 2005 Mercedes E Class E320, ultimately translates to a potentially less demanding ownership experience for those who appreciate accessible mechanics.
