Right there is no water loss or smoke etc but when heaters are on there is an oily smell coming into the car,now the mrs rang me earlier to say the spa gauge was reading 104 i said thats when the fan gauge was reading 104 i said thats when the fan kicks in so should be ok she got to my dads to drop the little lad off and got him to check that there was plenty of water in the header tank. kicks in so should be ok she got to my dads to drop kicks in so should be ok she got to my dads to drop the little lad off and got him to check that there was plenty of water in the header tank He said as soon as he tried to open cap it was boiling up like mad so ive just been back to pick boiling up like mad so ive just been back to pick the lad up from my dads drove there and back 20 mile checked when i got home same cant open the cap as its boiling up, so had a look about and listen and the hose from rad to thermostat you can hear boiling and its pretty solid. So my question is headgasket on its way or thermostat maybe (hopefully) blocked? Any help greatful