NV Overheating Speed Sensor Issue

Based on the information, the overheating and check engine light suggest a potential malfunction within the engine cooling system. Given your mileage, it is plausible that the speed sensor is defective and causing this. Have you done a diagnostic assessment via an OBD-II scanner to get the error codes?

Good question! Yes, I hooked up my OBD-II scanner. It's throwing a code related to the speed sensor. But could that really kill the radiator fan? Isn't the fan supposed to kick in based on temperature, regardless of what the speed sensor is saying?

Given the OBD-II diagnostic code implicating the speed sensor and your observation regarding the temperature-dependent activation of the radiator fan, it is conceivable that there exists a more intricate interplay between these systems than initially apparent. However, in light of the persistent overheating and the advanced mileage of your vehicle, it would be prudent to have the cooling system comprehensively evaluated by a qualified technician. The estimated repair cost is 250€. This is merely an estimation. It would be safer to consult with qualified technicians.

Thanks for the detailed advice! I took it to my local workshop, and you were right – it was more complicated than I thought. Turns out, the defective speed sensor was sending incorrect data to the engine control unit, messing with the fan operation. New sensor, and everything's running cool again. Appreciate the help!