After two years and 133,000 miles, my Mercedes E320 Diesel has proven to be a satisfying vehicle. Accumulating mileage has come with its share of maintenance, but as a hands-on owner with access to a lift, I’ve tackled most repairs myself, excluding only the SBC system work. Many issues encountered seem attributable to the car’s age and typical wear and tear, rather than inherent flaws in Mercedes-Benz engineering.
Over my ownership, several components have been addressed. The glow plug module, somewhat difficult to access, was replaced after triggering a fault code. While not strictly necessary at the time, all glow plugs were proactively replaced as preventative maintenance, and thankfully, they were easily removed using a torque wrench. An oil level sensor was also replaced, and routine transmission maintenance was performed, including a transmission fluid flush along with a new filter kit. Brake service, both front and rear, was carried out, alongside addressing front suspension work to replace worn rubber bushings. While not overly complex, the front suspension job did require a reasonable amount of time, and replacing both ball joints concurrently is advisable. Further addressing drivetrain wear, the transmission mount and intercooler seals were also replaced, and a starter motor was exchanged. The Sensotronic Brake Control (SBC) unit required dealer intervention a few months ago due to a fault code and dashboard warning light. Following some initial troubleshooting, a dealer appointment was made to resolve this specific issue.
Looking ahead on the maintenance horizon, some components within the 722.6 transmission are planned for replacement with Sonnax parts. This is preemptive, aimed at resolving occasional hard shifting when the car is cold during winter months.
Driving the E320 Diesel is genuinely enjoyable. It offers brisk acceleration, effective air conditioning, and commendable fuel economy. It excels in long-distance road trips and daily commuting, providing a supremely comfortable ride that truly “floats down the road.” One area for improvement, in my view, is the aging infotainment system. The MOST system feels dated, and a reliable Bluetooth integration solution is desired. The auxiliary 3.5mm input cable in the glove box, while functional, is not the most elegant or modern solution in today’s vehicles.
My ownership history with Mercedes-Benz diesels extends further back. I previously owned a W124 300D from 1992, a testament to robust build quality. It was an excellent car, though the air conditioning system wasn’t ideally suited to the Texas climate where I live. My father acquired that W124 and still owns it, with the odometer reading over 350,000 miles last I checked. He currently daily drives a 2006 CDI model with 89,000 miles, his second such vehicle, as the first was unfortunately totaled in an accident.
While considering newer diesel models from 2007 onwards, I’ve hesitated due to concerns about emissions control systems complexity and potential reliability issues. My 2007 5.9 Cummins diesel truck, with 261,000 miles, stands out as perhaps the most reliable vehicle I’ve owned and is notably easier to work on compared to the Mercedes, primarily due to the more spacious engine bay. However, comparing a heavy-duty truck to a luxury sedan is not entirely fair. Looking at more comparable vehicles, I also find the Mercedes E250 and the BMW X5d appealing, particularly the X5d for its increased interior space.
