i just put a new water pump and new top radiator hose on my van.

first of all, put the thermostat back in as it belongs there. you will cook the back of the motor without it. if it overheated before your repair, you may have blown a head gasket. get a shop to confirm. Roy

Did you try replacing the radiator cap? That's something easy and if you are just heating up and not overheating than that's most likely the problem.