<IMG alt=">" src="http://www.btinternet.com/~dave.riley32/set5/banghead.gif" border=0>FOR SOME UNKNOWN REASON THE HEADER TANK HAS STARTED TO BLOW THE PRESSURE CAP AS IF THE CAR IS OVER HEATED.

TEMP GAUGE IS ON NORMAL AND FANS KICK ON AND OFF
HEATER IS WORKING FINE
ALL HOSES ARE GETTING WARM APART FROM THE BOTTOM HOSE AND RADIATOR THAT IS COLD AND GETS LUKE WARM WAY AFTER PRESSER CAP BLOWS.
TRIED A DIFFERENT HEADER CAP STILL BLOWS.

FIRST THOUGHT WAS THE THERMOSTAT REPLACED IT AND STILL GOT THE SAME PROBLEM.
DONT THINK IT CAN BE A AIR LOCK AS THE HEATER IS WORKING.
NEXT THOUGHT WAS THE WATER PUMP STRIPED IT OFF AND ALL LOOKS OK .
RAD IS BRAND NEW AND BEEN ON CAR FOR ABOUT A MONTH WITH NO PROBLEMS.
BOTH HEAD GASKETS WERE DONE ABOUT 6 MONTHS AGO DONT THINK IT CAN BE THESE AS A HEAD GASKET WOULD NOT STOP THE RAD FROM GETTING HOT.

THIS IS NOW STARTING TO BREAK MY HART ALL ADVICE COMMENTS WELCOME

 

It could be air in the system, the other thing you can do is take the cap off when cold and run the car, with no pressure in the system, the water should not come out of the header tank, if it does then its either air in the system from when you had the rad done or the head gasket
But one last check, are all the hoses (when the system is pressured up) fully expanded (ie you cant crush them) which shows you the system is working properly, air in there will mean a hose is flexible when you squeeze it.

Tony