How To Drain Radiator. Wearing gloves and safety glasses carefully remove the drain plug at the bottom of the radiator to allow the fluid to drain into the pan. When there is no more water emptying out of the hose the system is drained.
Locate the drain valve at the bottom of the boiler. Install a tube on the radiator drain. Locate the drain valve at the bottom of the boiler.
Depending on the size of your coolant receptacle and cooling system you might have to empty it into a separate container to make room for the second draining.
Place the other end of the hose in the sink. Drain the radiator. Install a tube on the radiator drain. Make sure to tighten the drain plug and fill the radiator with fresh coolant.