I drive a 1995 Honda Civic EX, and recently it has been spewing coolant out of the radiator and overheating. Also, the idle speed would fluctuate. We found that there was a broken radiator cap, and replaced it. We refilled the coolant and the car ran fine for about a day. Then, it all started to happen again only there is no coolant spewing. We replaced the thermostat and that did not help. We also have been trying to bleed out the air from the system, and there is a lot of steam in there. We could open up the bleeder screw, and there would only be steam coming out for several minutes. There is coolant in the radiator and resevior tank, it just may be getting caught somewhere. Does anyone have any idea what may be wrong with it?