As part of the test, the engine oils in the four trucks with Euro 6D six-cylinder diesel engines were analysed in the OELCHECK lab every 5,000 kilometres. The limit values of the individual parameters were agreed with the vehicle manufacturer in advance. In this light, the following values came under particular scrutiny in the OELCHECK lab: any B100 fuel entry into the engine oils, a change in viscosity, oil oxidation and wear parameters. The short analysis intervals of 5,000 kilometres acted as a safeguard so we could intervene at short notice should serious deviations be detected and therefore avoid significant damage to the engines.
In all four trucks, the engine oils reached the 30,000-kilometre milestone – the point at which an oil change would otherwise have been due, according to the manufacturer’s instructions – without presenting any issues. The oil quality also returned good results at that point. The oil showed signs of ageing in the following 30,000 kilometres (up to 60,000 kilometres). However, this proved to be within scope. As expected, the fuel content in the oil increased throughout the test. The fuel entry was only proven to be moderate in all four vehicles observed, and the viscosity did not change as a result. The limit values agreed with the manufacturer were never reached, while wear metals could only be detected in low concentrations.
The analysis data showed that the vehicles’ oil should be changed every 90,000 kilometres. To be on the safe side, however, the vehicle manufacturer involved in the test approved extended oil service intervals of up to 65,000 kilometres based on the data established for the haulage vehicles used in long-haul transport.