ok, that my problem with a 94 civic dx. car would start, and sometime it would overheat. i would fill the resonator with water and then i drive the car. when i check the car again the resonator is empy, i would think headgasket but that only if the water is full. can it be my termostate

 

First check level in radiator/overflow. If low top off. Drive car check level. If level drops, sounds like a headgasket. Check your dipstick to see if coolant is mixing in the oil. Also, do you notice white smoke at all?

 

no white smoke, just chg thermostat, now i'm think water pump any suggestion

 

But your overflow keeps going empty correct?

 

yea

 

Well that shows something other than a water pump or t-stat. There is either a leak, or a bad head gasket. Try pulling the radiator cap off then run the car and check to see if you have bubbles in the radiator. If so you have a headgasket problem.