My wifes' mini has an airlock in the system,the fan seemed to run loud and long after stopping, I asked her when she last topped the rad up ,she replied"Never have done" . Needless to say the top-up container was empty, I undone the valve/screw on the top hose and let out the bubbles and air until it seemed to leak just water,but the problem seems be re-occuring.Anyone know how to bleed the system as I obviously have not got it right?