Had to replace the oilpan gasket(not for the faint of heart), did not disconnect the radiator(you can move it far enough forward to get the three bolts that hold the a/c compressor on) and in the process of reassembly found the outside temp sensor adrift. Reattached with a plastic wire tie. This morning(cold 32 deg) set off on a short trip and within a mile or so the temp read out on the display showed 122 deg(not). This was accompanied by a noticible loss of cabin temp although the engine temp guage was reading normally(half way). Checked the coolant level and found that to be where it usually is. Added a small amount of coolant just to cover the bases but this did not change the problem(lack of heat), when I say lack of heat it doesn't get nearly as hot out of the vents prior to all this screwing around still heat but warm not hot.. Any thoughts about this?
Nick

 

I had something similar happen on a different car ... the outside temp sensor got ripped off. With out the sensor attached the system 'saw' outside temp as below zero and the automatic climate control would turn heat on full blast .... which wasn't fun in Miami in July! Once sensor was replaced things went back to normal.

Suspect your sensor is not sending and system 'sees' 112 degrees as 'default' and is shutting off the heater ..... double check that the sensor is properly plugged in and consider replacement .. as I recall the one for MINI isn't particularly expensive.