have you looked in the oil to see if you have a blown head gasket? it will look milky with a blown head gasket...when you are bleeding the system are you seeing little bubbles coming up in the radiator fill? that would also indicate a blown head gasket...
another thing that concerns me is that if you have micro cracks in the block, you could be using coolent that way, but if you are overheating quick i doubt this, if you were saying "i fill the coolent, and drive it, and then its down on coolent and overheating and i everything is working and my head gasket isnt blown" then id say you have micro cracks in the passages in the block...so i dont think this is the case, but ill add it anyway incase someone searches down the road for over heating info...
MORE IMPORTANTLY, if you are running an e fan, do you still have a belt on your water pump? is your water pump working?
i dont try to fill through the reservoir, i fill through the rad cap, then you can see it burping out air and check for tiny bubbles...
plus it helps shaking the car to work air bubbles out of the system, i didnt believe it the first time i heard that, but i tried it and it helps...there are a lot of spots in the ka system where air gets trapped...
i highly doubt the car is overheating because it doesnt have enough coolent in it right away from start up, you should be able to fill the system up before it warms up, then when the thermostat opens fill it the rest of the way up...i think something else is wrong...