i have a 93 civic with a b16, when i got on the interstate my car overheated.

my temp gauge says the temperature is fine but all of my water has done boiled out of the radiator.

could it be the thermostat?

could it be the radiator? i still have the factory radiator in the car, should i put a si radiator in it?

 

Check your cap out themostat make and check your coolant pressure system

 

maybe air in the system? a thermostat is only a couple of dollars, you should just go ahead and change it

 

Change your thermostat and radiator cap. Should fix it.

 

buy those 2 items and if you have access or know somebody have them pressure check the system and see if it leaks anywhere

 

if the water already boiled out, chances are your headgasket went too.