last nite my shed of a escort xr3i decided to overheat that bad the temp gauge was almost coming back on itself.

straight away i thiught headgasket i managed to get the car home noticeing white smoke coming out of the exhaust

as i pulled up loads of steam from under the bonnet which i thought pressureised due headgasket and water everywhere

on closer inspection i took the head off to find gasket intact
i have noholes in rad or hoses

so what elese could it of been to cause this pressure and overheating any ideas
i pick my head up at 12 today and getting new rad to see what happens

could the thermostat cause this aswell as im unclear if it could or not

any help much appreiciated thanx

the fan was on aswell