My 2000 honda civic runs hot while parked a t a idle when driving or have the heat on its OK cooling fan is working put a new thermostat any suggestions

It may be time to replace the radiator, due to phosphate scale formation or corrosion. These links may help:

https://www.askmehelpdesk.com/cars-t...tml#post235973

https://www.askmehelpdesk.com/cars-t...ml#post1365453