Help needed.....I have a 95 Civic that recently started to overheat. It has overheated twice in the last 3 weeks. After it overheated both times I dumped a little less than a half gallon of water/Prestone into the radiator. It does not appear to be leaking anywhere and there is no white smoke coming from the exhaust. I changed out the radiator and thermostat a year ago. I have not had a head gasket check done yet. The car runs great. I am wondering what folks think. I am wondering if there could be a very slight head gasket leak or if there are some simpler things to look at first. It should be noted that tonight when it overheated, the overflow reservoir was full of coolant, yet the radiator was down as described above. Please help!

 

When the radiator is overheating, check if the fan is running. There could be an electrical problem that is causing the fan not to turn on. This will cause your car to overheat, especially in city driving.

 

Is it making any noise around the water pump.Why are you puttin water in it if it is not leaking?

 

Maybe its burning it, thats a common symptom of a blown head gasket. But you did say that there isn't any smoke, maybe the coolant is ending up in the crankcase. Pull the oil dipstick and check for more oil that you put in and any coolant on the stick. But i don't think you could get 1/2 a gallon of coolant in the crankcase.