i have a x reg 2.0l mondeo, discovered a water leak today. i have cured that then i topped the header tank back to between min & max and let the car run up to temperature with the cap off to let any air out of the system. the temp gauge is working and was showing half way but at the point when the fan kicked in the water in the header tank started to boil and spew out of the top. let it cool and the tank was empty, so put 3 litres of water in and tried again with the cap on, again water was boiling and right to the top of the tank. removed the thermostat and tried agin, did exactly the same. thats where i have left it.

anybody got any ideas? im thinking the worst at the moment

cheers Neil