How to Flush a Car's Radiator

Flushing your car's cooling system can help improve the overall performance of your vehicle. You can save yourself a few dollars by flushing your car's radiator out yourself rather than taking it into a mechanic. Flushing the system can be done by following the steps outlined below.

To complete this job you will need the following items:

  • A brand new plastic container that can store up to a gallon
  • A funnel
  • A wrench


  1. Park the car in a safe location out of the way of any traffic. You should attempt to park in a parking lot or a driveway where you can work without having to move the car.
  2. Make sure you let the car sit for a couple hours before you begin. The engine will need this period to cool off and for the fluids to return to a cool temperature. If you try and drain the fluid right after the car was running, the coolant will be extremely hot and has the potential to burn you.
  3. When the engine is completely cooled off and you can touch it with your hand without getting burned, pop the hood and prop it up using the prop rod. Place the new plastic container under the drain valve located under the radiator.
  4. Open the drain valve using a wrench and let the coolant to drain into the plastic container. Then close the drain valve once the fluid has been completely emptied.
  5. Fill the radiator with water and flush it out completely. This will flush out all the dirt and contaminants in the radiator that could potentially cause damage or the car to operate inefficiently. Drain the water out of the rad and into a separate container.
  6. Make sure the drain valve is closed and then re-fill the radiator with coolant by pouring the container back into the radiator using a funnel.
  7. Start the car and let it run for a few minutes while monitoring the gauges to make sure that the coolant is working and the car doesn't overheat.

If you notice any problems with the car or that the car is overheating you should take it into an auto repair shop where a professional can check the car for any potential mechanical problems. Only a professionally trained mechanic should work on a car's engine to fix potential problems, as they have the knowledge of how an engine works. For more information go here.