I have a mini one and it was leaking coolant, the garage changed the coolant exchange and all ok for 6 months then more leaking. I took it back to garage who changed part and water pipe but since this has been replaced the overheating symbols keep flashing yellow and red! I have taken it back to garage a number of times and they have drained it but the problem continues. The last time the heating failed aswell, only blowing out cold air, this was put down to an air lock. I have to take the car back again because aswell as the overheating symbols, the engine light came on(only once) and there seems to be loss of power. Can anyone give any suggestions as to why draining the system etc hasn't fixed the problem. The garage tell me that the heating works etc but it's only a day later and the problems are back, can anyone help with the loss of power etc, I have been reading the threads and now worry about head gasket problems even though I don't know if it's even related! I seem to get more problems everytime I get the car back!! It's all starting to get a bit stressful so any help would greatly appreciated. Thank you

If the engine is in fact overheating this will cause the engine to lose power as its running too hot, reasons could be a clogged core inside the radiator or its not been bled properly or maybe a hose has collapsed internally restricting water flow?
If youre no longer losing coolant then I doubt theres a problem with the head gasket.