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How to Recharge Freon in a GMC Sierra Truck

by Jeremy Holt

Pressurized freon gas is the component that keeps the air conditioner in your GMC Sierra cool. The gas is turned into liquid by a compressor then passed through an expansion valve where air, cooled by the freon, is blown into the cabin. Occasionally, the freon in the air conditioner needs to be recharged. To do this job at home, first purchase a refrigerant charging kit and a can of environmentally-friendly, R-134a refrigerant; it's available at any auto parts store and is compatible with the air conditioning system in all GM vehicles.

Start the engine and turn on the air conditioner; the charging process requires the compressor to be running.

Raise the hood and locate a canister wrapped in silver insulation at the back passenger's side of the engine -- this is the air conditioning accumulator. Remove the dust cap marked "L" from the charging port that runs over the accumulator.

Place the valve on the recharge kit onto the top of the refrigerant can and turn the valve's handle clockwise to draw out the stem and pierce the can.

Push the fitting from the kit's hose down onto the charging port. Turn the valve's handle back a little to retract the stem then listen as refrigerant flows from the can into the port.

Pull the hose fitting off of the charging port once the flow stops. Replace the dust cap and close the hood.

Turn the valve's handle counterclockwise and remove the hose from the empty refrigerant can. Discard the can but keep the hose to use next time.

Warnings

  • The system is under pressure so wear protective eyewear.
  • Adding more than one can of refrigerant will over-fill the system.

Items you will need

References

About the Author

Based in Middletown, Delaware, Jeremy Holt has worked as a writer, copy-editor and proofreader for MBNA Corporation, Rahli Inc. and Kreativz.com. since 1998. Born and educated in the United Kingdom, he holds a Bachelor of Science degree in psychology from the University of Glamorgan.

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