How to Drain Car AC System | 7 Different Methods Shared

How to Drain Car AC System

The car’s AC system is one of the essential parts of your vehicle. Ac system is used to cool down the air inside the car, but sometimes it can cause severe issues to your car’s engine. So you need to drain your car’s AC system at regular intervals so that you can monitor its performance and prevent the occurrence of any severe problems. 

How to Drain Car AC System

How to Drain Car AC System

The first step you want to take is to remove the radiator cap from the car and locate the drain cap under the vehicle. To remove it altogether, you’ll need a wrench. Next, place a bucket underneath the radiator drain cap to catch the antifreeze, which will drain when you remove it. Then, open the drain cap with a wrench. It will allow the antifreeze to drain until it is empty. 

Now, reinstall the drain cap tightly back into place with the wrench. Next, you will want to remove the fill cap from the radiator and refill the system with the new antifreeze. The final option is to fill the radiator to the right level with clean coolant.

7 Different Ways to Drain Car AC System

Way 1

The most common option for emptying the car A/C system is to connect the refrigerant condenser outside the vehicle A/C system. If this is not possible, an often-used method for emptying the system is to turn off the engine, remove all A/C hoses from where they are connected, open the radiator cap to release any pressure left inside and disconnect the high-pressure line from the compressor.

Way 2

Car air conditioning systems drain using the radiator; some use the overflow reservoir. Drain plugs are not used because they can usually be made of plastic. The radiator is the most common technique for draining a car’s air conditioning system because it is found on nearly all vehicles and has a large liquid capacity.

Way 3

Here’s a great way to clear out the air conditioning system. Just remove the air filter, put a funnel in the air filter box, pour all the air conditioning liquid into a container, and clean the air filter box. Then, start the car and turn on the air conditioning system to let all of the old liquid pass through the heater core, leaving the AC system clean and ready to be refilled. Make sure not to put the old juice back in, though.

Way 4

It can be quite a hassle to find a way to drain the air conditioning system of your car. That’s why we’ve written an article that’ll tell you how to get all of the air out as quickly as possible. You’ll also need some tubing and a safety canister. After that, you’ll need to find the low-pressure shutoff valve. 

It can be located in the engine compartment by looking under the hood. Then, you’ll need to double-check that everything is in the proper sequence. Lastly, you’ll need to open the canister and allow the refrigerant to flow through the system out of the exhaust pipe. Lastly, you’ll need to top up the system with the new refrigerant, and you’re good to go!

Way 5

Here’s a simple technique to drain the car’s air conditioning system. First, locate the AC drain valve. It is found on the bottom right-hand side under the hood. It’s usually a tiny faucet and is often left open because there isn’t much pressure in the system. 

Grab a socket wrench and loosen the valve. Once this is done, the AC should start to drain. Leave the faucet open for at least five minutes to drain thoroughly. After it’s finished, tighten the valve, close the hood, and you’re ready!

Way 6

It is time for you to drain the AC system and use a vacuum pump to remove the air from the system. If you can hear gurgling when you turn on the system, you will have to get inside your car and hopefully have a vacuum pump with you in the trunk.  

It might be a difficult task, so proceed with caution. Do not allow the vehicle to start and turn on the AC system. If it does not catch in time, this can cause water to gurgle in the system and onto the floor.

Way 7

The first way is to attach a hose between the low point of the system and an open container.  

The other method is to remove the soft point cap from the high side of the system, attach a hose, and open the other end to the outside air. The second method will be more effective at higher altitudes where the pressure may be more significant inside the container.

Frequently Asked Questions

How Can I Evacuate My Car AC Without A Pump? 

If you want to evacuate your AC without a pump, there are two ways. One way is by using vacuum gauges, and the other is by using a vacuum switch. A vacuum gauge is used when evacuating through a suction line, and a vacuum switch is used if the evacuation is not available through a suction line. 

How Do You Drain Freon From The Air Conditioner?

Freon is a gas commonly found in air conditioners. A quick way to drain Freon from an air conditioner is by inverting the device and removing the top installed with Freon. It will allow any remaining Freon to escape as a gas. It’s best to be safe and wear gloves, as some studies have shown that prolonged exposure to Freon can damage the respiratory system.

How Much Cost Does It Require To Evacuate The Car AC System? 

If you want the cost of evacuating your car AC system, you should know that removing all the old refrigerants from the manifold and receiver-drier is a process. This process typically costs around $50-$150 and will take two hours to complete.


The basic idea of a car air conditioning system is to remove the heat from the car cabin by condensing the water vapor in the air. The hot air from the house is pulled into the car’s engine compartment and cooled by the radiator, or if the vehicle has a liquid-cooled engine, the radiator is replaced by a heat exchanger.

The cooled air is passed through the air conditioning condenser, condensing the water vapor inside. The water thus produced is collected by a water pump and passed to the expansion tank, where it is fed into the air conditioning system again.