hi there i just bought a 316i on a n reg . when i driving along i lose my heat from my heater i changed my thermonstat thinking this would resolve the problem, but when u leave it ticking over the pipe which goes from the rad to the head goes rock hard, i lose heat from the heater and my car overheats can anyone shed some light on what the problem could be please

sounds like you have a leak. I know my car has a small one.. and when it reaches a certain point, it stops giving me heat at idle.

i had my car pressure tested today and turns out that my head gasket has gone