[Lance924]

I am having trouble with my 86 944.
The other night it decided to let go of all its water.I let it cool down and re-filled it but as soon as it got warm it would lose its water again though the header tank.I bled it but couldnt get any heat from the heaters.I had to drive the car home and after about 30mile the heaters came to life.
Sorry for the long story here.
I decided to change the thermostat today but i still cant get hot air though the heaters.I have bled the system time after time and still when it gets hot it will push the water out from the header.
I have also removed the top cambelt cover to make sure the pump is spinning,which it is.I have tried running the engine with one of the hoses off and dont seem to be getting any water pumping until i stop the engine,then water will be pushed out from the hose.
How can i check my pump without removing it,also has anybody else had the same problem(im sure they have)
Any ideas please would be gratefull
Cheers

Lance