Well last night I did my radiator flush. I built a cooling system flush 'machine' out of a 5 gallon bucket that hangs from the rafters in my garage. Then there is a ball valve in the hose coming out the bottom, then I made an adaptor for the radiator out of radiator hose and farm sprayer plastic piping. For the dirty coolant exit line, I made the same adaptor and had that go into an empty 5 gal bucket on the ground. It worked perfectly - as soon as the thermostat opened up, the dirty coolant came flowing out the hose while gravity pulled the clean coolant into the radiator. I first ran the car for 45 min with Gunk Super Heavy Duty radiator flush chemical, then flushed with 20 quarts hot water, then with 16 quarts Toyota Red. I have been driving it around today with no problems so far.
The parts for the flush machine cost me about $25 and a couple of hours of my own labor to build it. Way easier and with much less mess than draining the block and doing the heater seperately.
Andy