cheers frank but my car is filling the tank some times its not loosing water it was bubbling in the tank after use ive changed the rad cap now the bubbling has stopped but the tank is still filling and draining back in to the engine and ive now noticed the tank is brittle as the plastic tanks go over the years so im thinking if i can get a new one and try to work out whats up with the car Ive had it pressure tested which came up ok there no oil residue in the water or indeed watr in the oil so It doesn't look like head gasket though I suppose it could be the early signs of it