Hi there when I am in traffic my coolent/water starts boiling like a kettle and gushes out the top yet the car is not over heating and it starts when the car is around 80c but my fan is not kicking in iv bypassed the fan switch and it worked I have put a new switch on but still does the same could I b the thermostat or the head gasket please email me samsmy88@googlemail.com manythanks Sam.