need to know why my new thermostat want open up in my car. it keeps running hot?

What is your question?

We put AC Po in the make the cold air colder . An we had replace our thermostat an ring. An we got it to stop Linking. Now the thermostat want open an it's causing it run hot. An add more water every other mile an then it will go back to cold

What makes this problem better or worse?

it worse when you drive it a mile or two. it's better when you sit at a stop light

How long has your 2005 Ford Freestyle had this problem?

a week