grand voyager water probs
 

hi im a new member and just bought my first voyager, its a 2000[x] plate 3.3 grand voyager which i think is absolutely mint i love it however it has already presented a few problems. Firstly i am losin water out ov the header tank overflow and have to fill the radiator up with about a litre ov water every two or three days. I have checked the most obvious which are the head gasket wich is fine and the radiator and pipework wich again are fine and even the heater matrix as i hav no heat in the heaters and now im stuck!!!!!!! some one told me it could be thermostat but i cant find one all i can find is wot looks like a spark plug on outside with an electrical connector to it and when removed it looks like a heat probe like a miniture fish tank heater help anyone its drivin me mad lol the car is absolutely fantastic otherwise so can anyone please help or suggest wot the problem could be thankyou.