Why does my Audi A2's engine overheat when driving at high speeds?

I recently noticed that my Audi A2's engine temperature becomes abnormally high when driving at speeds over 100km/h. It never used to do this before, even during long trips on the highway. What could be causing this issue and how can I fix it?

It is possible that your car's cooling system is not functioning properly, causing the engine to overheat. This can be due to a variety of factors such as a faulty radiator, water pump, or thermostat. It is best to have a mechanic check and diagnose the issue.