Coolant temperature warning light

How to Bleed Your Car’s Cooling System

In Coolant by Josh SLeave a Comment

Get all the air bubbles out of your cooling system after a water pump or thermostat replacement can be really difficult. Your engine could easily overheat and you may damage your engine if you have not get out the air from the cooling system. I’m working as a mechanic and I have found a really good way to get out the air of the cooling system fast. This method can differ a bit between different car brands but the principle is the same. Follow this guide in step to step and get all the air out fast and safe.

There are some tools that will make this a lot more easily and faster, but not really necessary with this guide. You can use a Airlift Cooling System Airlock Purge Tool Kit Link to amazon to create vacuum inside the cooling system and get all the air out of the cooling system instantly. If you have the filling tap at the top of the radiator you could use a tool like the EPAuto Spill Proof Radiator Coolant Filling Funnel Kit Link to Amazon to make the filling more easily. If you do feel that you do not need these fancy tools, keep reading!


 1. Get your coolant/anti-freeze ready and fill up

The first step in this guide is to make sure your anti-freeze is ready. You should always use the correct coolant that is required by your manufacturer. The wrong type of coolant could damage your engine! If you are not sure of which coolant you should have, check your repair manual or contact your authorized dealer.

Generally mix the coolant with 50% water and 50% coolant ( If Concentrated anti-freeze). Always read the description of your coolant for the correct instructions.
If you are living in a cold country, you have to make sure that the coolant mix is correct. If your coolant freeze in your engine, you will destroy your engine. To check your coolant freeze level, you can use a REED Glycol Refactometer with ATC (C°) Link to Amazon .

If you have your coolant ready, we can continue to the next step.


2. Jack up the front of the car

A step that not many people do but will get you a much better result, is to raise up the front of your vehicle first. With this method, you will get the air out of the car a lot easier. Especially if your filling cap is at your radiator.

If you have a car with an external expansion tank, this may not be necessary.

To raise the front of the car you could either use a jack or put the car in a steep hill with the front up. If you are going to raise your car with a jack, check your repair manual for the right jacking points to not damage anything under your car. If you are going to use a jack, use a good jack and not the jack that is following with your car. These jacks are dangerous and have caused a lot of injuries. If you do not have a good jack at home and are interested to buy one, I can recommend the Pittsburgh Automotive 3 Ton Heavy Duty Quick Lift. It’s not expensive and you get a lot of value for the buck.

When raising up your car with a jack, always also use Jack Stands also to prevent any accidents.


3. Fill up your coolant

Now when the car front raised, it’s time to fill your coolant as much as possible.
If your engine has air bleed valves, open them at the same time as you are filling with coolant. Close them when there is flowing out coolant from them.

Anti-freeze is toxic and you should always check that your coolant is not flowing down in any wells on your floor. All coolant should be returned to your local environmental assessment. Keep in mind that if any animals drink the coolant, they can get very sick and it could lead to a death. Use anti-freeze with care!

When you have filled your coolant as much as possible, let the radiator cap to be open and go to the next step


4. Start the engine

You should now start your engine. The best way to do this is to get help from a friend. When you are starting your engine it could push out some coolant from the radiator if there is air inside. This is the EPAuto Spill Proof Radiator Coolant Filling Funnel Kit Link to Amazon becomes really useful to prevent any spill.


5. Turn the climate control heat to max

After you have started your engine you should now turn the climate control heat to MAX. Depending on the car, but many cars use a valve that will restrict the coolant from flowing inside the thermal pack in the car if the climate control is set to cold. Other cars redirect the airflow and not the coolant flow, so with these cars, this step will not make a difference. No matter which model you have, it’s an easy step to put your climate control to the MAX heat.


6. Rev the engine to 3000-4000 rpm

You should now rev up your engine a bit. This could cause the coolant to flow out of the radiator if you are not using the spill tool and I recommend to have a friend with you for this task. If you have a friend with you, you can loosen your air bleeding valves at the same time as your friend is revving the engine. Be attentive to any coolant temperature peaks and coolant leaks at this point.


7. Refill coolant if necessary

Close your air bleeding valves. Let your engine idle again and recheck the coolant level and lower the front of your car.
At this point, you should repeat these steps until you get heat inside the car and your coolant temperature reaches 90c. Rev up the engine again and do the loosen the air bleeding valves until there is only flowing coolant from them. Put your radiator cap back.

If your coolant temperature is now at 90c ( work temperature ) and you have heat inside your car. The air should now be gone from your vehicle.

Warning: Hot coolant can cause damages to you if it’s not used with care


8. Take a test drive

You should now make sure that you can’t find any leaks from after your reparation. If it seems good, take your car out for a long test drive. Be very attentive about your coolant temperature at the test drive and make sure the car does not start to overheat. Overheating can cause your head gasket to blow and you really do not want that to happen. Check all the functions and the temperature of the climate control.


9. Fill coolant again

If your test drive went well without any temperature peaks or other strange behaviours, open your hood and check your coolant level again. Check for any coolant leaks.
After this you can let your vehicle stand for a couple of hours, then take another test drive and do the same procedure and check for leaks and the coolant level.

After all these steps your reparation should now be successful. If any strange behaviours, repeat this guide or continue your troubleshooting. Check that guide out for any troubleshooting to your car. Many people replace parts without any troubleshooting at all. Don’t do that! Read our troubleshooting articles and learn how to troubleshoot in a proper way. Stop wasting money on replacing parts that were not damaged from the beginning.



  • Raise up the front of the vehicle is the best way to get all the air locks out of the cooling system
  • Anti-freeze is toxic and should be used with care
  • You can use tools to make all this a lot easier


I hope you liked this guide and your reparation went successfully. If you have any questions about this guide you can comment down below. If you have any other questions about your car that you want answers for. You can ask us to our homepage.

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