How to Recharge AC in Car (Easy Step by Step DIY Guide)

If you want to keep the cabin of your vehicle cool, you need to know how to recharge the AC in a car. If you have been wondering how to recharge my car air conditioner, we’ve got your answers.

In this guide, we look at typical AC recharge instructions and help you decide if the DIY auto air conditioning recharge is right for you.

How To Recharge a Car Air Conditioner (Step By Step Guide)

If you aren’t sure how to recharge the AC system in a car, we’ve got the steps you need. To get started, gather these supplies.

  • AC dispenser (should contain a low side gauge and trigger)
  • Meat thermometer
  • Cans of refrigerant (make sure you get enough for your car’s requirement and the right type)
  • Gloves and safety glasses

Unless you have experience performing a car air conditioning refresh, you should seek help from a professional. There are some automotive refrigerants that shouldn’t be used and special handling instructions of refrigerant that you need to follow.

If you still feel equipped to do the job, here’s how to recharge automotive air conditioning.

  1. Turn on the air conditioning system.
  2. Check the AC compressor to ensure it is engaging. You can find it driven by the car’s accessory belt. The clutch on its end will spin with the belt if it is working correctly. If it is moving, but all you get is warm air, you want to add refrigerant. If it’s not moving, you could have low refrigerant levels or a mechanical defect.
  3. Hook up the AC dispenser with the gauge to the low side port. Check the pressure while the vehicle is running. If the pressure reads less than 40 psi, the system is undercharged. It should read near 40 psi when everything is working normally.
  4. Attach the refrigerant can to the dispenser. Hold the can upright and squeeze the trigger for five to ten seconds. Watch the pressure gauge to ensure you aren’t overcharging the system. Stop when you reach 40 psi.
  5. Check the temperature inside the cabin with your meat thermometer inside the vents.

If you are still having issues after the car AC Freon recharge, it’s time to see a professional. It doesn’t do any good that you know how to charge the auto AC if there’s a mechanical problem causing the troubles.

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When Do You Need To Recharge Your Car AC?

  • Loss of Cooling Capability
    The most obvious sign of when to recharge AC in a car is when the air gets warmer. The problem might start off slow, but it will continue to get worse. In some cases, you might not notice it until the weather outside is much hotter.
  • AC Clutch Fails To Engage
    When you have the air conditioning system on the maximum setting, there should be a clicking sound happening as the clutch engages. However, if the levels drop low, the pressure switch doesn’t activate and the clutch won’t work properly. Keep in mind that this can be caused by mechanical failures as well.
  • Visible Signs of Refrigerant Leaks
    If you perform a car refrigerant refill and the system requires more down the road, you might be facing a leak. While you can temporarily do a car air conditioning recharge, the refrigerant won’t remain in the system as long as the leak is present. Instead, repair the leak and then perform the automotive air conditioning charging.

How Often Do I Need To Recharge My Car AC

Now that you know how to refill air conditioning in a car, you want to try out your new skills. However, you shouldn’t need to refill a car AC very often. If the cabin is getting warm more often than that, even though you just had a refill of the air conditioning in the car, there’s something else wrong with the system.

Recharge Car AC Frequency

Types of Refrigerants Found In Car Air Conditioners

Before you recharge air conditioning in a car, you must know what refrigerant type is appropriate. Different cars can use varying types of refrigerants. The information can be found in the service manual, and you should never use anything other than what’s recommended. Here are some you might need.


This is the newest type of refrigerant, and it’s designed to replace R134a. New car manufacturers have to make the switch by the release of the 2022 model release. According to the EPA, this type of refrigerant breaks down faster, causing less global warming.


Most cars today use R134a because it is safer and has lower flammability. It’s been used in most new cars that have been built since 1994, except for the newest models. It has also been replaced and won’t be used in any vehicles produced from the end of the year on.


Cars made before 1994 used R12 refrigerant. However, after this date, no new vehicles were allowed to use it because of the damage it causes to the environment. If your vehicle still runs on R12, you want to have it retrofitted for the newer options.

Types of Car AC Refrigerant

People Also Ask (FAQ)

How long does the recharging of the car AC take?

If you plan to do the job yourself, you want to know how long does an AC recharge take? If you are skilled, you shouldn’t need more than 30 minutes to get the job done.

How much does the recharging of car AC cost at a mechanic?

The average AC recharge cost professionally is around $100. The price depends on the car you drive and what other air conditioning services are being performed at the same time.

Can you run the car without recharging its AC?

The depleted AC system won’t usually damage any other part of the car. However, you won’t want to run the air conditioner if it’s not charged because it can lead to premature wear of the AC system components.

Do I need to add oil when recharging the car AC?

You don’t need to add oil every time you recharge the AC, but it should be done periodically. Having the right amount of oil included is essential for the longevity of the air conditioning compressor.


If you are planning on charging AC in a car, you now have all of the steps you need to get the job done. Follow our guidelines, but don’t be afraid to get help from your local service center if the job seems too complicated.

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Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.