Ok so lately my civic has been running hot(hasnt completely overheated on me but temp did reach the top of the meter) so im trying to figure out what my problem is. The radiator is new i got it in june. Usually the temp on the meter is a lil bit less than half but now when i drive on the street is starts to climb and eventually it gets to the top. The car is all filled with coolent and it has no leaks whatsoever. And when i turn on the heater the temp drops back to normal so my water pump should be good. Im thinking it may be my thermometer not opening to let coolent through. What do you guys think? Thanks for any help you can give