This is how it all started. I bought a 97 Civic ex and the AC wasn't cold/cool at all. I recharge it with one can of R134a and still no cold/cool air. I took the car to tires plus and have it diagnosis, they told me that I needed a new Ac Compressor and receiver drier. Bought a working AC compressor and a brand new receiver drier and went to precision tune to have them evacuate the hole AC system before I install the new ac compressor and receiver drier. After replacing the AC compressor and receiver drier and then charge it with 2can of R134a my car was blowing super cold air. Then next day I was driving on the freeway for about 20-30 minute I notice my temperture gauge started moving towards H. I got scaried, so I decided to get off the freeway and notice as I was slowing down or make a complete stop the temperture gauge would go back down to normal level. As I start to accelerate pass 25 on my speed, the temperture would start to move toward the H again and as I slow down or even make a complete stop it would fall back to normal level. I then replace the thermostat hoping that this was the cause, but it wasn't. One more thing, when the overheat occurs after being driven for 30 minute or so the hole top of the engine and by the radiator are all super hot. Not sure if this is normal? Haven't done anything further and would like to seek for all your helps out there. Note: I did check the antifreeze level and it was all level and there wasn't any leak.