How to Clean Out a Radiator at Home

Updated February 21, 2017

A radiator keeps a vehicle engine cooled. Properly maintaining a clean radiator is essential to your vehicle's performance. Over time a radiator can become corroded and clogged with dirt. Flushing out the radiator periodically, especially on older cars with high mileage, will greatly reduce costly repairs associated with radiator replacement. Rather than bringing your vehicle to a repair shop, it's easy to clean your radiator at home.

Open the bonnet and remove the radiator cap. The cap should have a diagram on top showing which way to turn it to remove it.

Remove the drain plug from the bottom of the radiator. The drain plug may by mounted on the bottom of the radiator facing the ground, or on the bottom inside facing the engine. This plug is usually plastic and removable with a screwdriver. Consult your owner's manual for the location of this plug.

Drain the radiator from the bottom and wait until it empties. Use a garden hose and run water through the radiator to flush out dirt or debris. Allow the water to run through for about 10 or 15 minutes.

Replace the drain plug and fill the radiator with water and coolant. Re-cap the radiator when it has been filled to capacity.


Always consult your vehicle owner's manual before performing maintenance. Ensure that the vehicle is not running when performing maintenance.


Using a stop leak in radiators can clog and eventually ruin a radiator. Flushing may take longer if stop leak has been added.

Things You'll Need

  • Garden hose
  • Screwdriver
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