flushing a heater core

knock on wood... it pours out rather slowly. I looked at it further and I found that the intake pipe was cracked at the weld into the core. still, though, when the tube is pressed in it does not leak out the crack, it just dribbles out slowly. I haven't tried the drano trick yet. With the intake pipe cracked, is it worth saving it? I would fix this one then buy new.
If I am not mistaken the old ones in our cars should be copper and you can solder that crack shut with a propane torch, It's worth a try, make sure you use plumbers solder and use alot of flux.