How to Burp Your Car's Cooling System





Introduction: How to Burp Your Car's Cooling System

This instructable will walk you through the simple process of "burping" or getting all of the trapped air out of your cars cooling system. This works for ALL Vehicles

If you have had any parts replaced on your cars cooling system (radiator, waterpump, new hoses, ect) then there is a chance that your cooling system has air trapped in it and this could make your cars cooling system operate poorly, or in worst cases minic the symptoms of a cracked  head.

So BEFORE you spend thousands of dollars at the mechanics having this done, try this and see if your cooling system operates normal (temp stays within normal , does not get hot or overheat).

Step 1: Things You Will Need

AnitFreeze or Dex cool, I used the 50/50 water dexcool mix

Spill free funnel ($20.00 on

Rag to wipe area clean

Time and Patience

Step 2:

Make sure that your overflow tank is at the level of coolant where the line marked "COLD" is, make sure that you car is cold, do not try this with a engine that has been running.

Open your radiator cap, insert the angled peice of the spill free funnel into the correct cap for you car, then the main peice of the funnel on that, Make sure that you have all conections on sung so that there are no leaks.

Step 3:

Now fill the funnel a little past half way, the reason for this is when your cars thermostat opens up the level will rise and drop with the opening and closing of it and with the escaping of the trapped air.


Step 4:

Go to your car, and set the climate controll settings to the hot or heat setting but make sure that the fan/heater is in the OFF posistion.

NOW you can start you car.

Step 5:

This is where the waiting happens, your car has to get up to temp so that the thermostat opens up to cool your engine, one this happens you will see the coolant level drop in the funnel, and a few to a large amount of air bubbles comming up from the coolant, this is the trapped air escaping your cooling system.

Sit back and watch this happen while enjoying a cold one, cuase in order to fully Burp your system the engine has to go through SEVERAL COOLING CYCLES........

I gave it the standard hour of running, if you still see air bubble comming out after that, check your overflow tank and make sure it has coolant in it. If it does not add some so the level is at the HOT line (becase you have now been running your car for awhile now).

The bubbles should stop and when it does turn your car off.

Step 6:

Now you will use the plug that came with the Funnel and plug the hole in the funnel so you can recycle or put the unused collant back in its container, do this with the plug in the funnel , put the funnel in the opening of your coolant container and lift up to remove the plug.

Take the funnels cap off of your radiator and put your cap back on, use the rag to wipe any coolant off of your car.

Now when you drive your car you should see a big differance in how it cools your engine. If you are still getting high temp readings  you might want to check to make sure that your thermostat is working and replace it if needed.



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    2 Questions

    I was trying to reply. It wasnt working... i have a failsafe thermostat that was installed about a month ago, water pump new radiator was about 2016 ...

    I would try the burping to see if that works if not you might need to do a pressure test, could be a bad head gasket, cracked head...ect, better to do the cheap fixes first and go from there

    If my car is overheating and the coolant comes out of the reservoir or the radiator if the cap is off, does that mean there is trapped air?

    the coolant level rises when the cars temp goes up, then goes to the overflow res, that is how it normally operates. did you check to see if your water pump is working? when was the last time you replaced your thermostat? since most antifreeze is mixed with water there is bound to be some air in your system. (first check to see if your thermostat is working) I like to use the smallest drill bit I can buy and drill a tiny hole in the thermostat (This hole will let some coolant through when the T-stat is closed, but no where near enough to effect the regular opening and closing like it is supposed to do. the hole allows for the air to escape the engine side and not keep the t-stat closed when it is supposed to be open)


    Hey i just replaced my thermostat on a 2013 jeep grand cherokee. Now my temp is running a bit higher than normal (gauge closer to middle) and I hear a gurgling noise when I start up and press the gas. Will this process help?

    yes, once you open up your system to do work on it for any reason you should burp it.

    Earlier, a reader posted this -

    "Worked great! I didn't even use the funnel. I took cap off reservoir let it run for 30 minutes and eventually it stopped burping. I put the cap back on..worked like a charm. I really thought it was a blown head gasket or bad thermostat. The temp was high and erratic and did overheat once. However after doing this burping procedure its steady and cool."

    I've been thinking about this ! Would the following procedure be a good way to do this ?

    With engine cold, fill radiator if needed. Place cold/hot control on hot. Add coolant to reservoir if needed to half full level. Leave cap off of reservoir. Start engine and let it idle. Add coolant to reservoir if needed. When "bubbles" disappear from reservoir, turn off vehicle. Adjust reservoir coolant level as needed.and replace cap.

    yes , and no, yes because that is basically what the funnel lets you do, but NO, because when the thermostat opens and closes the coolant level rises and lowers, and coolant would spill out of your radiator. so when you use the spill proof funnel it prevents the coolant from spilling out while letting you visually see if there are air bubbles still coming out of your radiator.

    I would check to see if your coolant level is low. make sure your car is cold, then start it up with the radiator cap off and see if the level is low. but you could have trapped air if the levels are good. This certainly will not hurt your system, go for it.

    I just finished the process tonight for about 35 more gurgling noise so that must have been trapped air. Thanks mfrontauto?

    Glad this helped

    04 Honda Civic, let it run for an hour and the bubbles never stopped, the reservoir is a bit overfilled. The coolant also started to look dirty after about 30 minutes, could be corrosion from inside the engine. Any suggestions to get it to stop bubbling? Elevate the front end? Thanks.

    Worked great! I didn't even use the funnel. I took cap off reservoir let it run for 30 minutes and eventually it stopped burping. I put the cap back on..worked like a charm. I really thought it was a blown head gasket or bad thermostat. The temp was high and erratic and did overheat once. However after doing this burping procedure its steady and cool. Very happy ( 2002 Cadillac Deville DTS )

    glad I could be of help