What is the cause of Kia Ceed's engine overheating?

I have a Kia Ceed that keeps overheating, even after replacing the coolant. What could be causing this issue?

It is possible that there is a leak in the cooling system, causing the coolant to constantly need refilling. Have a mechanic check for any leaks and repair them as necessary.

Another possible cause could be a faulty thermostat. If the thermostat is not opening properly, it could be preventing the coolant from flowing through the engine and causing it to overheat. Consider getting the thermostat replaced.

If the coolant and thermostat are not the issue, it could be a problem with the water pump. The water pump is responsible for circulating the coolant through the engine, and if it is malfunctioning, it could cause the engine to overheat. Get the water pump checked and replaced if necessary.