ive just baught a 325i as a daily user to keep my blue oval out of the shit weather,

the car overheated ( turned the car off within seconds of light coming on ) as i got stuck in some snow outside the house, so i checked for mayo and nothing as i thought headgasket, checked the water pump and it was knackered so replaced that and the thermostat, car stil overheats, so i thought dodgy thermostat so changed it again, stil overheats but no mayo, so i then run the car without the thermostat in and stil overheats, also the pipe from the engine returning to the radiator was cold and should be quite warm / hot, no water circulating the in the system

so i thought airlock so i flushed the car with water and all flows fine, put it all back together and it seemed ok, car was gettin warm inside, the return pipe was hot so the thermostat is working and water is flowing, had the bleedscrew open ( header tank cap on) on the rad for a good amout of time to get rid of any air, shut the bleedscrew and left the car over 2 hours and was fine temp styed bang on in the center then i went out and it boiled again, checked for mayo again and still no trace

also i thought the viscous fan but it seems ok but shouldnt need it in this weather anyway

now im in a pickle as i dont hav a clue what could be rong, im thinkin it could be a majour airlock or headgasket,

any ideas???????????? cheeRS