Step 3: Pour a Radiator Flush Product Into Your Car. After the old coolant from your car has drained completely, it’ll be time to perform your radiator flush. Use a product like Irontite Thoro-Flush to get the job done. Thoro-Flush is capable of cleanin

Using pre-diluted coolant, as opposed to concentrated or full-strength, is an easy, no-fuss way to ensure your radiator has the proper 50/50 mixture of coolant and water. Run the engine until the cooling system stops bubbling and the coolant level starts

To flush a radiator, start by draining all of the old antifreeze in the radiator into a drainage pan. Then, seal the drain valve and pour a full bottle of radiator cleaner and 1 gallon of distilled water into the radiator reservoir.