How to Remove Radiator Rust

Updated February 21, 2017

Part of the regular maintenance of your vehicle regular is to regularly clean and flush its cooling system. If you don't do that, rust will form in your cooling system that could cause your car to overheat. Once you do have rust in your radiator, a good flush will get it out of the system.

Open the bonnet of your vehicle and locate the radiator. Open the radiator cap and place it to the side.

Place the bucket underneath the draincock on the radiator. It is a knob at the bottom portion of the unit, which can be easily removed. Unscrew the draincock and drain all of the coolant out of the radiator. Once the radiator is drained, replace the draincock.

Pour radiator flush into radiator. Then put the hose in the filler cap and fill up the radiator until it's done. Replace the cap on the radiator.

Start the vehicle and turn the heater on high to the hottest setting. Once the vehicle reaches the normal operating temperature, let the vehicle run for about 10 minutes.

Allow the engine to cool. Once you can place your hand on the top of the engine and let it sit for at least 10 seconds without burning your hand, place the bucket underneath the radiator and drain the coolant from the system.

Replace the draincock on the radiator once it had drained completely. Fill the radiator completely with water, and repeat step 4.

Drain the radiator once the engine has cooled per the instructions in step 5. Then close the draincock.

Fill the radiator with a 50-50 mix of distilled water and coolant. Close the radiator cap and shut the hood,

Things You'll Need

  • Hose and water source
  • Distilled water
  • Coolant
  • Radiator flush
  • Bucket
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About the Author

Russell Wood is a writer and photographer who attended Arizona State University. He has been building custom cars and trucks since 1994, including several cover vehicles. In 2000 Wood started a career as a writer, and since then he has dedicated his business to writing and photographing cars and trucks, as well as helping people learn more about how vehicles work.