Can you flush a radiator with a garden hose?
You can flush a radiator with tap water, but it won’t be as effective as using a flush. The flush has corrosive properties that will actually get all of the old antifreeze, rust, and scale cleared out. And while you can use water from a garden hose to flush the system, it is recommended to use distilled or de-ionized water for your final flush or for mixing with antifreeze.