What could make my 2000 mercury cougar v6 run hot

What is your question?

2000 Mercury Cougar v6 blew the top radiator hose replaced that it still continued to run hot changed thermostats twice still keeps running what could be wrong with my car now I have no heat whats so ever if the car is in idle it doesn't run hot but when u drive it the car runs hot not only that but when the car runs hot I have heat when its not running hot I have no heat please help

What makes this problem better or worse?

Better idle with water

How long has your 2000 Mercury Cougar had this problem?

3 weeks