Peabody wrote in news:20101216-001312.310.0 @news.astraweb.com:
The water pump is at the back of the block, kitty-corner to the upper rad hose. You won't be able to reach it with tubing stuck into the upper hose outlet.
I suppose it might work, at least to a degree. Provided you managed to get the end of the siphon hose right to the bottom of the water jacket through the upper rad hose outlet, you'd be able to remove /most/ of the quart that's in the block.
But you'd still leave enough behind to compromise the new coolant and reduce the corrosion protection to the baseline 2-years, just as though you'd never tried that. Corrosion attacks the head-gasket first, and that's a very bad thing.
What you can do in lieu of pulling the block drain is to drain and fill the coolant as you just did, every two years. No need to remove the rad, just open the rad drain and let whatever wants to drain out, drain out (turn heater to full-hot first). That way most of the coolant will be fresh most of the time, and corrosion protection should be mostly OK.