6 Easy Steps to Add Freon to a Car

Have you ever had a feeling that your car AC doesn’t work efficiently? The situation that this piece of equipment stops cooling adequately is not rare at all. However, there is no reason for concern since, in approximately 80% cases, the problem is connected with lacking freon in the AC.

The question is how to add freon to the car. In fact, the procedure is not that complicated, and a lot of people decide to do it on their own. Start with visiting a local car shop where you can purchase freon and needed equipment to perform the refiling. Let’s start adding it to your vehicle.


Never use R-12 freon as it is dangerous, plus you can’t find it legally. Nowadays, it is replaced with R-134a, and just a few certified services can use the old type. So, if your AC requires R-12 freon filling, you need to make an appointment with an official service.

Also, keep in mind that recharging freon to your AC can be dangerous if not done correctly. Therefore, if you think you are not skillful enough, you should not hesitate scheduling freon filling in the registered service.

Equipment Needed for Adding Freon to a Car

Once you decide to refill your AC with freon, you should buy necessary supplies, such as:

  • Freon gas
  • Thermometer
  • Hose with a gauge for recharging

If you want to avoid purchasing that hose, you can ask your local AC service to lend you this piece of equipment. In some cases, it can be possible.

The best option is to use a thermometer to check the AC temperature before adding freon. Turn on your car and put the AC to the highest and coldest blow. After several minutes, it is time to measure the temperature. If it is over 70 F (21 C), you will need to add freon.

Before buying it, you need to check all available information online, on the radiator cover cowl, or in the AC car manual. Take care to use the appropriate freon for your system.

Safety Measures

Since freon can cause frostbites if applied directly to your skin, you should wear a shirt with long sleeves and rubber gloves to protect your hands while manipulating with it. It is also recommended to wear protective goggles to protect your eyes.

Keep in mind that freon is also a highly hazardous gas, and you shouldn’t release it in the atmosphere. Therefore, be careful and strictly follow the procedure of recharging.

Since your car needs to run during the freon recharging procedure, you should watch out not to touch any other parts of the vehicle, especially hot ones, to avoid hurting yourself.

How to Add Freon to a Car

1. Connecting


Before starting, you need to make two connections. First, connect a car freon system to the hose. Second, attach the other side of the hose to the freon can.

Since the freon system in your car has two ports, you need to find a low-pressure one and connect it to the hose. In most cases, you will recognize it thanks to a mark with the capital letter L.

Don’t worry! You can’t mistakenly choose the high-pressure port since it doesn’t match the size of the hose valve.

After connecting both sides, you can continue with the procedure. Find a gauge in the middle of the hose and check the pressure in the system. If the pressure is less than 40 psi, it means the AC needs charging.

On the other hand, if the pressure is 50 psi, it is too high, and your AC can’t work efficiently due to the overcharged system.

2. Purging the air

Purging the air


It is a necessary step that will allow the purging of the system. All you have to do is to open the valve and release freon for a few seconds. Then close the valve and prepare yourself to proceed.

3. Charging the system

Charging the system

Since you need to turn on the car and set the AC to the coldest and highest mode, it is an excellent idea to ask someone for help. That person can turn on the car while you try setting the AC.

Always wait for at least 30 seconds until the compressor of the AC system starts working. When you see the pressure on the gauge falls, it is the moment to open the can tap and let the freon enter the system.

Sometimes, you will need more than one can for refilling. It is always the best solution to follow the indications on the gauge to define precisely when the system is filled enough.

If you need one more can, you should make sure to close the freon tap before replacing it with a new one. Be careful and stop refilling as soon as the gauge shows that the pressure is correct.

4. Freon cans

Freon cans

There are a few mechanisms regarding freon cans you need to take care of before beginning the job. Therefore, always read instructions noted on the packaging and pick out the procedure depending on the type of chosen freon can and manufacturer.

Some of them have a system that you should keep upright and take care not to turn it around. On the other hand, there are models you need to turn upside down before recharging the system.

Most freon cans have the tap to open, but you can find models with a plunger valve, as well. In that case, you will need to press that valve while the freon can is upside down to start charging.

5. Checking


Keep in mind that your car needs to run while pouring the freon. That way, the AC will start working more efficiently. Check the temperature all the time by the thermometer. Once the temperature is lower than 64 F (18 C), you should stop recharging.

6. Disconnecting the freon

Disconnecting the freon

Never turn off the car before disconnecting the freon kit. You will avoid most problems by leaving the engine to work until disconnecting the low-pressure port. When it happens, the system will automatically close the port.

Then put a cap to the low-pressure port back. If the freon can is still full, you should close the can tap and disconnect it from the hose. That is the moment when you can turn off the car. Well done!