Hi all I've brought my first zafira which is the Arden blue zafira gsi I've owned it for a year now and I've just hit a problem when driving for around 20-25 mins the car starts to blow steam out of the water tank the heat gauge doesn't rise over half way but the tank is going crazy and the computer screen is telling me coolant low now if I let it cool down it doesn't need filling if I slightly open the cap when it's boiling it completely goes mad and there is no water left after a steam explosion what wrong I now cant use this car after 20 mins any ideas
