How to Charge Auto AC With Freon

by Michael Larkin

Freon is what keeps your vehicle's air conditioning unit producing cold air. Over time, though, the freon can be depleted, leaving you with an air conditioner that will not produce cold air. Any mechanic can quickly recharge your freon, but if your car was manufactured after1994, you should be able to recharge your car's freon yourself.

Consult your vehicle's service manual to determine the kind of freon it uses. If it was manufactured after 1994, it should be R134a freon. If it requires the older R12 freon, you will not be able to charge it yourself and will have to consult a mechanic.

Locate your vehicle's service fittings for the air conditioning system, using your service manual. Determine which is the low pressure fitting and which is the high pressure fitting. The low pressure fitting should be smaller.

Attach the service hose to the can of R134a freon. Turn the hose's valve until it punctures the top of the can.

Turn the valve out slightly to release a small amount of freon and blow existing air out of the tube. Sucking air instead of freon into the car's air conditioning unit could damage it. Close the valve quickly after blowing air out.

Connect the service hose to the low pressure fitting, holding the can upright.

Start the engine and turn the air conditioner on maximum. Either have someone else start the car so you can hold the can upright, or secure the can so that it will not tip over.

Open the valve on the service hose. Wait 10 minutes for the air conditioning unit to absorb all the freon.

Turn off the engine. Close the valve on the service hose and disconnect the hose from the low pressure fitting.

Items you will need

About the Author

Michael Larkin has been writing since 2005. He has worked as a photojournalist for CBS affiliates in Spokane, Washington, and Boise, Idaho. He has also freelanced for ESPN and PBS. Larkin currently writes a wide range of material, including corporate newsletters, blogs and ad copy, as well as the occasional magazine article. Larkin holds a Bachelor of Arts in journalism/mass communication from Whitworth College.

Photo Credits

  • photo_camera Klimaanlage pkw image by crossgolfing from