Seat Ibiza Diesel Overheating Problem

I had a similar car overheating issue with my Ibiza. The engine light was also on. Check if your radiator fan is running constantly at full speed or not at all. For me, the thermal switch was the problem. It's responsible for regulating the fan speed based on the engine temperature. A faulty switch can cause the fan to malfunction, leading to overheating.

Interesting, thanks. Was the fan noise louder than usual then? How did you figure out it was the thermal switch and not, say, the fan motor itself? Did you do any specific tests?

Yes, the fan noise was noticeably louder, almost like it was stuck on full blast. I initially suspected the fan motor, but after doing some research, I found that a faulty thermal switch is a common issue on Ibizas and can cause similar symptoms. The best bet is to get the car scanned for error codes; that should point you in the right direction. However it sounds very similar, so I would suggest going to a workshop.

You were spot on. I took it to a garage, and they ran diagnostics. A faulty speed sensor was indeed the culprit. They fitted a new sensor and cleared the error code, and the fan's behaving itself now. Temperature control is back to normal. It cost me 250€ in total. Thanks for pointing me in the right direction!