any one ever replaced the heater core?

[JDmills]

I think I have a hole in my heater core. There is a sweet smell when I first turn on the heat in the morning. Any one ever done this job? I cannot even immagine how to get to it. Of course the Haynes manual does not even mention such a job in it's pages.

Also, does any one know how to drain ALL the coolant out of the engine block? I drained the radiator, and replaced the thermostat last month, but only got a little more than a gallon of coolant out. seems like there should be almost another gallon in there, but I cannot figure out how to get it to drain. It needs to be done, as I later discoverd that the car had green antifreeze in it, and I refilled it with the G-05 stuff... the coolant had so much rust and sediment in it that it looked, well rusty but pinkish, until the rust settled out a couple of days later. Now I have to drain and flush, the mixed junk out. All adivce welcomed
Thanks,
Jason