IvorMog, your Q is in no way insulting. All good:) The thermostat remained and it works. It is just the new effect when I drive faster than lets say 130 km/h. There is a significant hotter engine temprature than with the original smaller radiator. Normally you will expect a better coolant capacitiy with the bigger surface of the new aluminium one. And this works as expected e.g. when being in a stop and go situation.