Seat Leon Hybrid Overheating Issue

Sounds like a dodgy air intake flap motor. Had a similar issue with my old Vauxhall Astra. Check engine light kept popping up, and the cooling system went haywire. First thing to do is pull the fault code. What code are you getting? If it's related to the flap, the motor is probably shot. It's a common problem. Do you notice any difference in engine performance or fuel consumption?

I did get a fault code, but I didn't write it down. I will check it again. Where is the flap motor located? Is it easy to access? Is there any way to test if the flap motor is defective?

Yeah, sounds like the exact same issue I had. The flap motor is usually somewhere near the radiator, controlling airflow to the engine. Access can be a pain depending on the car. Testing it without proper tools is tricky; you'd need to check the voltage and signal being sent to the motor. Honestly, save yourself the headache and take it to a workshop. They can diagnose it properly and replace the faulty part. Running the engine with a malfunctioning cooling system can cause more damage in the long run.

Took the Leon to the workshop, and you were spot on. They confirmed the active air flap motor was faulty. The replacement and labor cost 590€. Thanks for the advice.