How to Flush Your Car Cooling System


Beyond the comforts presented by being able to regulate the temperature inside your car, your auto’s heating and cooling systems are essential in averting your ride from breaking down due to extremely high operating temperatures. It’s particularly vital to check your auto’s heating and cooling systems during the weeks foregoing the subfreezing winter season and the sweltering heat of summer. But it’s usually advisable that you check these systems every time you perform a routine maintenance on your car.

When you drive, your car’s radiator uses a mixture of coolant and water to help in lowering the temperature in your car’s engine system. Just like any other liquid, coolant has a propensity to breakdown over time and this is the reason why you need to replace it once in a while. During the replacement there are some steps that you need to follow for a successful flush out and changing the coolant without imperiling the environment. Check the following steps on how to flush your cars cooling system.

Materials required

  • Fresh coolant
  • Radiator cleaning fluid
  • A large container with a tight-fitting lid

#1: Wait for your engine to cool

If you were driving then you need to park your car in safe place away from animals and children. Wait until the engine becomes cold before you begin working on the hood. The parking brake should be on.

#2: Prop up your hood

Ensure that you have turned off the engine. It’s pretty much the same way you would want to turn off any electrical device before you start fiddling with its components.

#3: Find your radiator pressure cap and release it

Do this cautiously. If your car has been running just before you prop up the hood, even though the engine is already cold there is still a chance that there is a pressure build up under your radiator pressure cap. If you release the cap quickly, the cap and the radiator content might just fly off. You should avoid this by being more careful.

#4: Look at the petcock that will let you drain the radiator

If you are not familiar with this technical part then consult your user’s manual or any supplementing document for reference.

#5: Position your container underneath the petcock

The empty container will hold the drained fluid that comes out of the radiator.

#6: Release the petcock

Allow the coolant to completely drain into your container. Ensure that the liquid doesn’t come into contact with the ground or into a storm drain. After emptying the radiator, close the petcock and remove the container holding the drained coolant

#7: Fill the radiator with water

Note that this is just plain water required at this step and not water-coolant mixture. Do not replace your radiator cap yet.

#8: Start the car’s engine with the heater control on High

As you add the radiator cleaning or the coolant cleanser into the radiator let the engine keep on idling. Depending on the amount of time specified by the manufacturer of you cleanser, you may need to leave your car idle for that amount of time usually 20 to 30 minutes. Keep an eye on the temperature gauge to ensure the engine doesn’t overheat. If your car has an engine temperature warning instead of gauge, then shut it off immediately it lights up.

#9: Turn off the engine and allow it to cool completely.

When the radiator is cool enough to touch, bring back your container and drain the fluid on it again by reopening the petcock which is normally under the radiator. After successful draining, close the petcock.

#10; Fill the radiator with water for the second time

This is very important as it will clean your radiator from mineral deposits and gunk completely. Start your engine again and leave it to idle for around 5 minutes. After the 5 minutes, turn off the engine and drain off the water from the radiator into your container and then close the petcock.

#11: Bring your new coolant and follow all the instructions provided in the manual.

Most vehicles need a 50-50 mix of water and coolant. If your user’s manual instructions states otherwise then follow them. The mixture should reach the ‘MAX’ line on the coolant recovery reservoir or cover the fins in the radiator.

#12: Disperse the water and coolant evenly throughout the system and finally replace your radiators cap.

Run the engine with heater on High until the temperature gauge reads normal range.

The aforementioned steps highlight a detail way of how to flush your cars cooling system. If you follow these steps well, you will successfully flush out your cooling system.

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