I just replaced a head gasket, water pump, and thermostat on a 95 ex. Also flushed out the radiator and it's flowing well. I start the car and get it to normal operating temp and the thermostat opens but coolant will not flow through the lower radiator house. There are no blockages anywhere and the head was taken to the machine shop and milled and pressure tested. Any ideas on why the coolant isn't circulating?