1990 Chrysler Van water pump

Hi:
Is the engine overheating? Also, if the radiator is new, and the waterpump belt is working and spining the pump, either the new t-stat isn't opening or you have a rad hose pinching shut. Check the hoses when the car starts to get hot. Also, if you decide to remove the t-stat again, place it in a pot of boiling water to see if it opens.

Let me know what you find.

Joe