Chrysler 300m overheats if running, but will idle with no ill effects. Ideas?

What is your question?

Problem is constant and was present when car was purchased. Why is wasn't returned to car lot for refund then I know not. Im just trying to help someone who knows nothing about cars-and I mean nothing. Told that pump, thermostat, and radiator all replaced. Also reported as no leaks, no noises, etc. Now u know what I know. Any suggestions would be helpful.

What makes this problem better or worse?

No idea. Was told issue was constant. Overheats if driving, doesn't if idling

How long has your 2002 Chrysler 300M had this problem?

Unknown