I have a 2003 Honda civic ex. I have been having a problem with it overheating and not being able to maintain coolant levels in either the radiator or the reservoir. Could this be a blown head gasket? There are no leaks in the system. The oil doesn't look out of the ordinary. I am adding about a quart of coolant a day to it.
Okay, if the engine is overheating, the coolant can evaporate. Have you checked the thermostat? Has the radiator been flushed? Are the cooling fans turning on? Finally, can you see any evidence of a leak around the cylinder head? If nothing is in the oil, then it would have to leak out of the engine if there is a loss of coolant.