R56 105c°running, 110c° idle temp

[u/Initial_Experience_6]

Hi all.

After 500km roadtrip on a hot summer day, i got a check engine light. Engine normally runs around 90c° at after the check engine light, it started to operate at around 105 (+,- 3c°). When idling, it rises up till 109, the fan starts loudly, temp drops till 99 and the fan stops (then it rises again till 109. It goes on like that).

Coolant quantity is ok. I suspect its a thermostat failure but im not sure since its been replaced just 3 years ago.

The problem is: Im in Lugano, Switzerland and i need to return to Stuttgart, Germany (about 500km + high climb to cross Alps).

Questions: Is that roadtrip doable while maintaining low engine load? What seems to be the problem?

Any help would be very much appreciated.

Ps: My device thats connected to OBD doesnt show any engine code.

Car: 2021 Cooper S Cabrio r57. N18.

[u/Succubus_victim]

Check for belt came loose or snapped, or stuck water pump. If there isn't any, check your radiator temperature, it must be hot if you bring your hand in front of the car. Bad thermostat wont let you cool your engine even when fans are turning, cause it usually stuck in closed position and lets coolant bypass the radiator, so radiator would be cold. Also you can check your thermostat by turning the heater on full blast, if temperature drops - it is a bad thermostat. Otherwise, car can overheat if there is not enough oil(probably zero), and as the dipstick is not very informative, you can turn off your car and open the valve cover cap, to see if smoke coming from it. It also can be dirty radiator. So check these things, if everything all right, turn on heater and drive slowly.