I have just been brought home from Hastings in a freezing cold recovery van. My car has overheated twice in the last 2 days. I filled the water resevoir up and as the water temperature gague reaches 110 the water disappears and it boils over and the water resevoir fills with hot water. I am thinking its probably the thermostat but, the question is - where is this located and where are the bleeding points ??