INSTALLING A BLOCK HEATER Radiator fluid is normally used to keep engines cool. On really cold days you can use it to do the opposite. Keep an engine warm. This makes starting an engine much easier. In this video we install what is called a "Lower Radiator Hose Heater" This 500 watt heater is like a little kettle. It warms up the coolant that travels throughout the engine. Installation is simple. We did it all in less then 30 minutes. You can purchase a heater like this online or at your local auto parts dealer. All you need to know is what size fits your radiator hose. If your not sure what size hose you have just take it off and bring it to the store with you.