hi ive replaced the headgasket on my mk3 2.0l duratec engine also had a new head fitted which was pressure tested first, new thermostate and new temperature gauge but when running he car the system pressurises and boils over the fan kicks in at 110 as shown on scanner. Any ideas what could be causing this please

 

Header tank cap?

 

fooked water pump maybe or an airlock?

 

replaced the water pump

 

Take the thermostat out and see if it still does it.

 

its a new thermostat

 

doesn't mean is working correctly though m8.