How to Recharge AC

How to Recharge AC

Recharge your A/C in 30 minutes with a special recharging kit

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.
Overview: Assess the cooling problem and buy an AC recharge kit

Quick disconnect fitting for AC recharge charging port

This fitting in some recharge kits makes a quick, solid connection to the AC recharge charging port.

If your A/C system 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 a job 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 refrigerants 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 product shown here 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 vehicles 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.


Refrigerant can cause frostbite and serious eye injuries if used improperly. Follow all the cautionary information in the kit instructions, and wear gloves and goggles during the procedure.

Recharge your A/C system

Photo 1: Find the right port for your ac recharge,  compared the tubing size going to each A/C charging port. The thicker tubing is the low-pressure line and the one to use for recharging.

The port with the smaller tubing is the wrong one.

Pop the hood and find the low-pressure line and port (photo 1). Then connect the gauge (photo 2). Check the pressure reading on the gauge. If it reads zero, your system is completely empty and this repair won’t work. You need to take your vehicle to a pro. If the gauge shows some pressure, start the engine and turn your A/C to “Max” and the fan to “High.” Then check the compressor clutch (photo 3). If it’s spinning, add refrigerant until the gauge reaches the recommended pressure shown in the instructions. But don’t overfill! Too much refrigerant actually reduces cooling.

If the compressor clutch isn’t spinning, add one-half can of refrigerant. 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 pro mechanic.

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

Protect the Environment

Just because you can keep recharging your A/C yourself doesn’t mean you should. Leaking R-134a harms the environment by contributing to global warming. If you recharge ac 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.

Required Tools for this AC Recharge Project

Have the necessary tools for this DIY car ac recharge project lined up before you start—you’ll save time and frustration.

  • Pliers
  • Safety glasses

You’ll also need plastic gloves.

Required Materials for this AC Recharge Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.

  • A/C recharge kit

By the DIY experts of The Family Handyman Magazine