How to Recharge a Car AC

Updated: Apr. 01, 2024

Complete a car AC recharge in just 30 minutes with a special recharging kit. Plus, find out the environmental impact of charging a car's AC.

Next Project

30 minutes






Improve the cooling of your car's air conditioner with an easy-to-use A/C recharge kit. You can do it in four simple steps. We also tell you when it won't work and when you should take your cooling problem to a pro.

Tools Required

  • Gloves
  • Safety glasses

Materials Required

  • A/C recharge kit

If your car’s air conditioner blew ice-cold air last year but barely cools now, chances are it lost some refrigerant over the winter. That happens in older vehicles when the aging seals contract and some refrigerant leaks out.

Topping off a car ac system can usually put you back in the deep freeze. That’s an easy DIY car repair you can do yourself if your vehicle was made after 1993 and is filled with R-134a refrigerant (check the label under the hood or the specifications section of your owner’s manual to be sure).

Note: Some states impose restrictions on the sale of R-134a refrigerant to consumers. In some cases, the cans may have a different design, requiring different charging procedures. Recharging AC won’t fix all A/C problems. But if you’re willing to gamble about $50 on a recharging ac kit, you might be a cool dude in less than an hour. You can save about $100 in labor costs by doing the car ac recharge job yourself.

Stop at any auto parts store and pick up an R-134a A/C recharging kit. I used the A/C Pro Recharge Kit product because it came with a reusable gauge and a quick-connect fitting, and the refrigerant contained a seal conditioner additive. But you can use any brand for a car ac recharge.

Warning: The electric AC recharge compressors in hybrid cars are incompatible with the oils and seal conditioners used in many retail recharging kits. Using the wrong auto ac recharge kit can result in a lethal electrical shock. Check the car ac recharge product’s label for compatibility with your hybrid vehicle before buying. If you’re not sure, take it to a pro.


Be careful when performing this project as you will be working near hot and rapidly rotating parts and belts in your vehicle’s engine compartment. It is important to wear the appropriate clothing, eye protection, and follow all the precautionary instructions on the refrigerant kit manual as improper use may cause frostbite or serious eye injuries.

Project step-by-step (6)

Step 1

Quick disconnect fitting for AC recharge charging port

Make sure that you choose a recharge kit that includes a quick disconnect fitting because these are easy to install and provide a secure connection to the A/C charging port during use.

How To Recharge Your Car's Air ConditionerFamily Handyman

Step 2

AC charging port

Pop the hood and find the low-pressure line and port. There are two ports on every A/C system, one for high pressure and one for low pressure. We need to look for the low pressure port, which is typically located near the accumulator of the vehicle. Fortunately, recharge kits with quick disconnect fittings will only fit on the low pressure port of the air conditioner.

Alternatively, if your recharge kit does not have a quick disconnect fitting, compare the tubing size going to each A/C charging port. This thicker tubing is the low-pressure line and is used for recharging. The port with the smaller tubing is the incorrect one.

How To Recharge Your Car's Air ConditionerFamily Handyman

Step 3

Connect the gauge hose

Connect the fitting to the port by unscrewing the port cap and setting it aside in a safe place. Shake the can to mix the refrigerant and the sealant. Remove the safety tab from the can, and while supporting the A/C’s tubing with your fingers, squeeze the connector onto the port in one quick motion. Check the pressure reading on the gauge. If it reads zero, your system is completely empty and this repair won’t work. You’ll need to find a mechanic to perform the necessary A/C repairs on your vehicle. If the gauge shows some pressure, start the engine and turn your A/C to “Max” and the fan to “High.”

How To Recharge Your Car's Air ConditionerFamily Handyman

Step 4

Check the compressor clutch

Examine the center of the A/C compressor to see if the clutch is spinning or stationary. Don’t confuse the clutch with the serpentine belt pulley. If it’s spinning, it is okay to add refrigerant until the gauge reaches the recommended pressure range shown in the instructions.

If the compressor clutch isn’t spinning, add one-half can of refrigerant following the directions below. If it then starts spinning, continue adding refrigerant until you reach the recommended pressure. However, if the clutch won’t spin after adding half a can, stop. Your leak is too serious to handle with a top-off—it needs a professional mechanic.

How To Recharge Your Car's Air ConditionerFamily Handyman

Step 5

Charge AC

Hold the can upright and squeeze the trigger (or open the valve). Then rock the can from 12 o’clock to 3 o’clock until the gauge needle is sitting in the recommended “green” pressure range. But don’t overfill it! Too much refrigerant actually reduces cooling.

When you’re done, disconnect the hose connector and reinstall the port cap.

How To Recharge Your Car's Air Conditioner Fh12jau 530 13 202 Grid Fh2 Surfscreen With CalloutsFamily Handyman

Step 6

Protect the Environment

Just because this is an automotive task you can DIY doesn’t mean you should keep recharging your A/C yourself. Leaking R-134a harms the environment by contributing to global warming. If you recharge your A/C and it runs low again in a few months or before next spring, you’ve got a fairly large leak. Take it to a pro and get it fixed. While you’re at it, get to know how AC uses gas for running.

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