[patrickt]

I've done this a couple of times. There's absolutely nothing to it. I'm not even sure how I would give a tip on it other than avoiding the air pockets that accumulate. If you put in a new thermostat, drill a couple of holes in it as per the manual's suggestion. I don't even think you need to flush it, just drain it all out, then fill it up so the overflow tank has maybe an inch in it, then tilt your nose up and crack the upper petcock on the radiator, run the engine to get it warm, if you have a stubborn air bubble, loosen a manifold fitting towards the front and see if you can bleed the air off there. I like a 50/50 mix of conventional green and distilled water from the supermarket. I throw a bottle of Water Wetter in too and I change it all out every three years. It actually looks as good coming out as the new stuff going in.

Edit -- and there's a drain petcock on the bottom driver's side of the radiator, you can't miss it.