leave the drain plug in. take the top hose off the rad. t stat out, push the upper hose down, it will pump out the upper hose. when it stops coming out, the rad is dry, add the water, at this point your pumping clean water through the engine, so just dump say 2 gallons in asap after it stops pumping out the upper hose. if it pumps out clear before you need the 3 rd or 4th gallon, your done.


no need to run the heater, its got coolant running to it full time, no off valve.