The tank isn't a header tank
It's an expansion tank....
It only needs enough water to cover the indicator , no more
The radiator is filled through the filler neck ( it may take a couple of goes to work out the airlocks, as mentioned )
As the coolant expands and contracts dependent on temperature the expansion tank will either fill slightly or thermosyphon coolant back into the system
Simon @ Sifab.co.uk
