On the trip from Peru to Bolivia, our car had already sparked pure excitement among local rally fans. They kept taking selfies with the red X 220 and bombarded us with questions about the vehicle. But since we arrived in Argentina this has become even more extreme. The Mercedes X-Class will not just be available here as of 2019, it will actually be manufactured in the land of gauchos and steaks – added to which, pickups are extremely popular here. Our “Bomberos Camionetta” (fire rescue pickup) encounters numerous admirers at every traffic light and filling station.
After a 4,000 km trip (2,485 miles) over what were at times very poor dirt roads, we are pleased to note that the Mercedes engineers have done an extremely good job, especially when it comes to the chassis. Moreover, the 285/60 R 18 General Tire Grabber AT³ tires make a great match for the vehicle, while the polished 18” Delta aluminum forged wheels add to the Bomberos Camionetta’s great looks. We even stored one of the complete wheels in the original spare wheel carrier, where it also fit perfectly.
One of the greatest challenges of the Dakar Rally is crossing the Andes.
This holds true for the drivers as well as for the vehicles. The lack of oxygen at such high altitude results in a loss of engine power of up to 50%. The combustion mixture is low on oxygen and unless the engine control unit reduces the fuel supply accordingly, too much fuel is burned. This will lead to an increase in combustion temperature and thus to engine damage.
This year, German rally participant Markus Walcher experienced just that: the spark plugs of his Rover V8 melted at an altitude of 4,500 metres (14,764 ft) and destroyed the engine. But this is not just a problem for the rally cars.
The service vehicles also suffer from these symptoms, especially the diesel vehicles that have to meet current emission regulations (Euro 6). The engine control unit of many vehicles is unable to cope at such extreme altitude and either completely shuts down the engine or switches to fail-safe mode. Our Mercedes X 220 d ran flawlessly at an altitude of 4,500 metres (14,764 ft), given that only 50% of its engine output was available.
The only problem we encountered was that the diesel particulate filter became clogged and we had to burn off the soot by taking the car on a high-revving 50 km (31 mile) drive, which had the desired effect.