How To Burp Vehicle’s Coolant System?

The coolant system in your vehicle may not work as it should, even when all related components are running fine. To your utter dismay, your cooling system may not adequately cool the engine even when there is enough coolant in the radiator. But what could be the cause?

This could be because of trapped air in the cooling system hindering the coolant from getting to the engine. Where the radiator works as it should, burping the coolant system will be the solution.

If you replaced or worked on any cooling system components like the radiator, water pump, radiator hoses, etc., there’s a chance that air will get into the system during the replacement. It will cause the cooling system to work poorly or display cracked cylinder head symptoms.

Here, Rxmechanic will walk you through a simplified process of how to burp a coolant system. At the end of this article, you may also know how to tell if the air is in the cooling system.

how to burp cooling system

Step By Step Process On How To Burp Coolant System

Before you spend hundreds of dollars on your local mechanic to fix this issue, see how the cooling system runs. Does it stay within the average operating temperature? Does it overheat or not get up to the average operating temp? Now, let’s look at how to burp the radiator with a funnel.

Items needed

  • 50/50 Antifreeze
  • Clean rag or towel
  • Spill-free funnel
  • Time and patience.

Step 1: Park your car

Park your vehicle on a level and strong pavement. Ensure your radiator and the overflow tank are at the appropriate level. If the engine is cold, the coolant level should be on the COLD mark. If the engine is hot, then the coolant should be at the HOT level.

Step 2: Insert the spill-free funnel

Remove the radiator cover and plug in the angled piece of the spill-free funnel. Then, place the main piece of the funnel on it. Ensure you fix the connections properly and there’s no leak. Check the funnel kit for instructions on how to connect it.

Step 3: Fill the coolant on the reservoir

Pour coolant into the funnel and let it go above half. This is to avoid coolant spillage when you start the vehicle. Start the car and allow it to warm up. Once the engine gets to the average operating temperature, the thermostat activates, allowing the coolant to rise and fall as it opens and closes. The trapped air escapes as the coolant rises and falls.

Open the vehicle door and set the climate settings to heat or hot. Switch the fan/heat setting knob to the OFF position. Turn on the vehicle.

Step 4: Start the engine

Turn on the vehicle and allow it to run. Now, you need time and patience. Allow the engine to run at the average operating temperature so the thermostat will grant coolant passage to cool the engine. Once the thermostat opens, the coolant on the funnel will drop, and you’ll see air bubbles coming from the radiator. That is the trapped air getting out of the system.

Give it time to complete its course. Remember, the engine must undergo several cooling cycles for a complete system burp.

Allow the engine to run for 30 minutes to 1 hour. If you notice air bubbles coming out, check the overflow tank and ensure there’s adequate coolant in it. If there’s no or low coolant in it, pour in coolant till it gets to the HOT mark. (This is because the engine is running hot now, so it shouldn’t be on the COLD level).

The air bubbles will stop once there’s no trapped air in the system.

Step 5: Finish

Now, remove the spill-free funnel following the instructions on the funnel kit and recycle the coolant into a container.

Tighten the radiator cap and clean any coolant spills around the area. Test-drive the vehicle. You should see a big difference in how the cooling system cools the engine. If your temperature gauge needle is still pointing north, check if the thermostat is still functioning as it should and replace it if necessary.

Frequently Asked Questions (FAQs)

How long does it take to burp the cooling system on a car?

Burping a car cooling system requires time and patience. Depending on the amount of air in the cooling system and your vehicle make and model, burping will take up to 30 minutes to 1 hour.

However, it takes about 5 to 10 minutes for the engine to get to the average operating temperature. It’s this time that the thermostat will activate to grant coolant passage to the engine.

How do you get the airlock out of coolant?

First and foremost, airlocks are air bubbles in the cooling system that stop the adequate flow of coolant within the system. This may cause the system to overheat. Hence, it is essential to know how to burp a closed cooling system to get rid of airlocks.

Removing the airlock from the engine coolant requires the following steps;

Mix the coolant with water or get a 50/50 coolant mix and fill the radiator and the overflow until they are both filled.

Remove the radiator cover. Start the engine and allow it to run. Monitor the instrument cluster and ensure the temperature does not go higher than it should.

After some time, the coolant level will drop. You will observe air bubbles on the radiator, which shows the airlock is getting out. Once the air bubbles stop, the airlock has been evacuated from the system. Refill the radiator and replace the cap.

How do you burp coolant without a radiator cap?

How to burp a cooling system without a radiator cap is the same way you do it from the radiator cap. But here, you’ll do it from the overflow tank.

Remove the overflow cover and switch the heater settings to max full. Fill the reservoir tank to the COLD mark. Start and allow the engine to idle for 30 to 45 minutes. The coolant will drop as the trapped air escapes from the cooling system.

How do you burp a motorcycle radiator?

Burping a motorcycle radiator is pretty similar to a car cooling system.

Most coolants are entirely loaded and ready to use. Some come with a 50/50 mixture of coolant and distilled water. That way, you don’t have to add anything to it.

To burp a motorcycle radiator, pour coolant into the cycle radiator and gently shake the motorcycle. Then, start the bike and throttle it several times to completely bleed the system. Check the fluid level one more time and top it off when necessary. Pour the coolant into the radiator and cover the radiator cap. You’re ready to go.

Now, remember that this is necessary only for coolant-cooled bikes.

Final word

Airlocks can make a well-functioning system act as if it’s malfunctioning. Air pockets can accumulate over time in the cooling system lines and cause engine overheating if overlooked. Hence, it is essential to learn how to burp a coolant system.

You may wonder what happens if you don’t burp your cooling system when there’s a need for it. It will cause the engine to overheat, leading to severe engine damage. This article has provided all the information you need to burp a radiator.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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