Megane Overheating Slow Warm Up

Sounds familiar! Is your temperature gauge acting erratically too? It could be a faulty temperature sensor, but thermostats are common culprits. Have you checked if the cooling fan is running constantly, even when the engine is cold?

The temperature gauge seems to be working okay, just slow to rise. The cooling fan isn't running constantly, which makes me think it's not the sensor. Could it also be the water pump, even if there are no leaks? Or does it really sound like the thermostat?

Nah, if the fan isn't going crazy, the sensor is likely fine. A faulty water pump usually causes more dramatic overheating. Honestly, the slow warm-up combined with overheating points straight to the thermostat being stuck open. I'd get it checked at a workshop, they can confirm it pretty quickly.

Thanks! I appreciate the input. Looks like I'll book it in for a thermostat check then. Hopefully that's all it is. I'll post a resolution when it's sorted. Expecting to pay around 350€ for the repair.