Why would your 1997 Windstar have no heat and have a lot of pressure in your radiator and over heat - you have changed radiator cap - hoses and thermoastat and the motor is rebuilt?

* A water pump failure could cause this.

* If the pump is turning backwards due to the serpentine belt being improperly installed

* but it sounds like a bad or mis-installed head gasket would be the most probable.

Another suspect: thermostat installed backwards