Re: slightly worrying problem
sounds like an air lock like the other guys said, go to your car and open the coolant tank filler cap thing, start the engine and let it idle for a minute or so. open the bleed valves, not to sure where they are on the tspark. look around for a valve that looks similar to the valve on your tyres and follow the pipe and it should go back to the radiator. now get someone to rev the engine to get the water flowing round and when you get a steady stream flowing out the bleed valve, stop revving the engine and let it idle and put the cap back on whilst the water/coolant is pouring out. !!!IT WILL BE HOT!!! so be careful, then just top up your coolant levels with whatever you use!!! the heating prob is linked to the coolant so should work perfectly after that. if not, maybe a new heater matrix is needed. any more info pm me.