Cooling system flush
 

If I flush and bleed the cooling system (engine running with radiator cap off), should the running engine still push the coolant out of the radiator's neck and thus still overflowing or the coolant level in radiator should stay constant? My overflowing (with the old defective head gasket) can be seen here: http://www.volny.cz/veitel/prelude/o...t/overflow.mpg (1.2MB). I'm changing my head gasket now so I need to know what to expect.

running a motor with the coolant cap off will cause the fluid to overflow as the fluid expands when it gets hot.