Even without the thermostat open, when you look in the top of the radiator, you should see flow from where the steam pipe hose comes in. Once the thermostat is open, you will see flow from the tubes in the radiator and eventually you will have to put the cap on, because it will start to overflow.

 

its fans. car over heats when parked/ going slow. not at freeway speeds, and not with the ac on. fans. if it was a water pump not spinin it would overheat all the time.

 

From what has been said, the fans obviously work. The suggestion was made to investigate whether they are coming on by temp as they are supposed to. I don't think that has been addressed. When that is done, solutions may be more apparent.

 

Radiator clogged?Water pump?