6 weeks ago i baught my 94 civic ex 5 spd drove it home ( 2 hours ) with no problems. Starting about 2 weeks ago my car started to overheat after 20 to 30 mins of driving. I changed the coolant as well as the thermostat. I turned the heat on high and noticed it blew cold. I let the car go to normal temprature with the cap off let it cool then topd off. I have no visable leaks or burning smell but after the car is ran it seems alot of coolant is missing. I dont have a bad head gasket and my lower radiator hose does get warm and i have seen my electric radiator fan kick on once right before it got near redline but never seen it other than then. Im so lost need help.

 

well if you have no heat then you may have a blocked up heater core. It could have air in the system. What brand thermostat was installed? what temp rating is the thermostat?

The coolant is going somewhere....how are you so positive the HG isn't leaking/blown?

Lisle brand tool part # 75500 will tell you whether or not there is exhaust gases in the coolant, which means a blown HG or not.

there are many things it could be.. need more info and you need to do the dye test to see if gases are present in the coolant.

 

The stant thermostat suppose to open at 170 and car dosent drive rough at all no smoke comming from anywhere. I started the car reved the engine to 3 rpms a few times a friend said there was no bubbles comming out of radiator.

 

I didnt see any oil in the coolant

 

OK

but you say it has no heat?

is the hoses going in and out of the heater core hot?

 

I havent checked but when the engine is really hot and i turn the heat on ( or at least try to ) the air stays cold and it dosent stop the overheating. I would thing the air would warm up regardless if the heating core since its using the engines heat

 

no your engine supplys the coolant to the heater core which provides heat inside the car.

Two hoses go to your heater core one is the in the other is the out. Both should be quite hot to touch if everything is in working condition.

Have a second person Look at your heater control valve which is "in line" with your inlet hose all the while you are IN the car moving the CC (climate control) selector from hot to cold and back and forth...does the heater valve move properly (open/close)