Can anyone help me my girlfriends fiesta keeps telling me that its overheating the temp gauge goes past the red and then drops back to normal, it has never boiled over though. Ive fitted a new heater control valve and i dont no if ive done something wrong can any one shed any light on this, do they have a common fault with a temp sender or something, any ideas would be much appreciated.

 

sounds like the tempurature sensor, quite common, on the early zetecs it was in the thermostat housing, not 100% on yours tho