coolant system, crack in antifreeze resvoir tank on 2005 BMW 325i

the antifreeze leaking, stall on highway, continue to fill withantiifreeze trying to get home, went thrugh 3 bottles, we thought a hose had a hole in it,come to find out the tank that is the resvior for the antifreeze has a crack, why would this happen, and my window washer fluid will not release fluids, and my gas tank will not close why

Asked by for the 2005 BMW 325i
the radiator, coolant reservoir, hoses, thermostat housing are all made of plastic. someone will need to pressure test the system to find the leak. do not put this off; these engines overheat very easily and can be
damaged beyond repair. find a good independant BMW shop
that other people recommend.