i have no water in oil no white smoke etc......but keep lossing water had a new rad fitted as old one was leaking and just cant seem to solve the problem. i have topped car up again tonight ran the car with cap of expansion tank then once heaters where hot put cap on again sat in the car and you could hear water flowing through the heater matrix i have never known this to happen. i have checked carpet and it dry very strange i really need to get to the bottom of this water loss. the car is a astra g 14 16v any help appreciated