With the thermostat open their is suppose to be a good amount of force/pressure that pushes the engine coolant out of the block to the radiator to cool it down. That's what I'm not getting. The radiator is fine it works. I'm not getting the water back out of the block so it can cool down.. I can drive for an hour and open the radiator cap and not get sprayed. That's the "pressure" I don't have