okay i drive a 94 Civic LX Sedan, my car was recently over heating, when i would pop the hood, all the antifreeze in the resvoir tank was literally boiling. Last week i changed the radiator to a brand new one, but as time passed my car over heats while im stopped but when in drive it goes back down to normal temp they told me it might be my thermostat but i need to make sure any ideas what can it be im running a D16z6 auto tranny

 

Usually a head gasket.

 

if its warm sitting still and cools off when you take off its the lack of a fan or lack of an operational fan.