it looks like you may have an air lock in your system may be the heater matrix , try flushing the system with a hose pipe first to eliminate blockage , ( not knowing the car model ) then run to temp and gently undo the plastic screw on the cooling hose ( if fitted )for about 30 secs and make sure no air comes out , probaly will , then tighten screw , turn off engien let cool and check water level, restart and let warm up then check heater dont forget to top up with antifreeze , coolant , hope this helps .
""""even thou i am a retired mechanic I can not be hold responsible for any injury caused as this is just for advice to tell a qualified Machanic
Ray, February 2009
