Car Maintenance 101: Flushing your Vehicle’s Cooling System

The Importance of your Vehicle’s Heating and Cooling System

Beyond the comforts offered by being able to control the temperature inside your vehicle, your auto’s heating and cooling systems are necessary in preventing your ride from breaking down due to incredibly high operating temperatures.

Checking your auto’s cooling and heating systems is particularly crucial in the weeks preceding the subfreezing winter season and the sweltering heat of summer. But it’s more advisable that you check these systems every time you conduct a routine car check-up or you engage in basic vehicle maintenance.

Every time you drive, your radiator uses up coolant and water mixture to help lower the temperatures in your vehicle’s engine system. The longer and the faster you drive, the bigger the stress on your engine, allowing temperatures to skyrocket to incredible heights leading to the increase of the likelihood of overheating. Because of the coolant’s crucial role in maintaining your engine’s efficiency, you need to keep your ride equipped with the right coolant mixture (pretty much the same way you’d pick out the right type of gas for your car).

Coolant, like all the other fluids used by your vehicle, has a tendency to break down over time. This is why you need to replace your coolant mixture once in a while. When the coolant breaks down, more stress is placed on your radiator and your engine begins to run hotter than normal. Gunk and mineral deposits also build up under your vehicle’s hood, effectively reducing your vehicle’s overall performance. Prolonged use of bad coolant can also result to radiator damage, requiring you to replace your radiator sooner than you actually have to.

How Often Do You Need to Flush Out Your Cooling System?

The frequency required by your vehicle may depend on the type of auto you own and the weather conditions. If you live in an area that has moderate climates, then you can flush out your vehicle’s cooling system once a year. If, however, you live in an area known for its harsh winters and/or sizzling summers, then you may need to change your coolant mixture twice a year—at the start of summer and at the start of winter. Browse through your owner’s manual for more information on this matter.

The following are some steps on how you can flush out your vehicle’s cooling system.


  • a large container (or several large containers)
  • radiator cleaning fluid or coolant cleaning system
  • fresh coolant

Step 1: Wait until you have a cool engine. If you’ve been driving, then it’s always best (not to mention safer) to wait for your engine to cool down before you start working under your vehicle’s hood.

Step 2: Prop up your hood. Again, for this step, make sure that you’ve turned off your vehicle’s engine. It’s pretty much the same way you’d want to turn off your computer, or any other electrical gadget for that matter, before you start tinkering with its components.

Step 3: Find your radiator pressure cap and release it. Do exercise a lot of caution when doing this. If your car has been running for a bit before you prop up your hood, even if your engine is already cool, there’s a chance that pressure build-up has occurred under your radiator pressure cap. When you release the cap hastily, the cap and the radiator content might just fly off. Avoid this scenario by being extra-careful.

Step 4: Look for the valve or petcock that will let you drain your radiator. If you’re unfamiliar with this auto part, then I highly suggest consulting your owner’s manual or any other supplementing manual as reference.

Step 5: Take your empty container and put it directly under the petcock or the valve. The empty container(s) will catch the draining fluid that will come out of your radiator.

Step 6: Release the petcock or the valve. Coolant should drain completely into your container. Let the coolant drain completely.

Step 7: After emptying your radiator, close your petcock or valve and remove the container.

Step 8: Fill up your radiator with water. Take note: not water-coolant mixture, just plain water. Don’t replace your radiator cap just yet.

Step 9: Start your engine. Let your engine idle for a bit as you add your coolant cleanser or radiator cleaning fluid into your radiator. Depending on the instructions or the time specified by the manufacturer of your cleanser, you may need to let your vehicle idle for around 20 or even 30 minutes.

Step 10: Turn off your engine. Let your engine sit until it cools down completely.

Step 11: Drain the fluid from your previous container and position it under the radiator.

Step 12: Reopen your petcock or valve (usually found at the base of the radiator) and let the mixture drain.

Step 13: After draining completely, close your petcock or radiator valve.

Step 14: Remove the filled container and drain it once more. (You’ll be using your container again)

Step 15: Fill your radiator with water. Although this is the second time you’re doing this, it’s important that you keep on repeating this process to clean your radiator from gunk and mineral deposits completely.

Step 16: Start your engine once more but this time, let it idle for just around five minutes.

Step 17: Turn off your engine and once again, using your container, drain the water from your radiator. Remember to close your petcock or valve completely after draining your radiator.

Step 18: Bring out your coolant or antifreeze bottle and follow the instructions specified in your owner’s manual. Most vehicles require a 50-50 mix of coolant and water. If, however, your owner’s manual states otherwise, then follow its instructions to a tee.

Step 19: Replace your radiator cap.

If you’ve followed all the 19 steps listed in this post, then congratulations! You have just successfully flushed out your cooling system.


5 Responses to Car Maintenance 101: Flushing your Vehicle’s Cooling System

  1. Mr.Nissan says:

    All I see in this picture is money getting thrown away if that leaks not fixed.

  2. […] Source: Auto Mechanic | Auto Mechanic Repair and Maintenance Tips […]

  3. […] I read his entry on how to flush your car’s cooling system I knew I had to share this wonderful site with all of you do-it-yourself mechanics out there!  I […]

  4. autofrankie says:

    Well, Mr. Nissan, you’re actually right there. If you don’t get any type of leakage in your auto fixed as soon as possible, consider a chunk of your savings good as gone. :)

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