And some important issues only become apparent when looked at a second time: for example, how do panelling materials such as sheet steel or plastic react with each other, as they have different expansion coefficients depending on the temperature.
How does the elastic adhesive used in side panelling react in extreme sub-zero temperatures if the steel frame remains rigid, but the plastic panelling contracts.
Tests are carried out on the engine and the exhaust gas aftertreatment, the transmission and all the peripheral components for the drive system. To do this, the test vehicles are prepared for the cold-start test by standing over a whole weekend with the engine flap open, to ensure the engine has completely cooled down. Even the temperature in the oil sump is down to minus 25 degrees or lower. And even experienced engineers allow themselves to smile when, in such conditions, a heavy diesel engine starts up after just a few seconds and immediately ticks over - even at minus 30 degrees Celsius.