How to Recharge an Air Conditioner in Cars

by Contributing Writer

The air conditioner in your Chevrolet car may need to be recharged with refrigerant throughout the life of the Chevrolet car. Signs that your system needs more refrigerant include when you notice warm air coming out of the vents while the air conditioner is on or you perceive that the air conditioner is just not working to its full capacity. The refrigerant is a chemical responsible for cooling the air as it's blown through the vents of your vehicle. You can pay a mechanic to recharge your air conditioner, but this can be rather expensive.

Under The Hood:

 How to Recharge an Air Conditioner in a Dodge Dakota

Allow the Dodge Dakota to cool down for a half hour. This will prevent any injury or burns while working under the hood of the vehicle.

Open the hood of the Dakota and locate the air conditioning unit and service fittings. If needed, refer to the owner’s manual. Both service hoses come off the compressor. The low-pressure fitting runs to the accumulator and the high-pressure fitting goes to the condenser.

Connect the recharge hose included with the R134a kit to the valve on top of the R134a can.

Turn the valve on the R134a on, doing so will open the can and allow coolant to be released. Turn the valve off immediately to avoid loss of extra refrigerant.

Attach the recharge hose to the low-pressure fitting on the compressor. Begin the Dakota’s engine and set the air conditioner to the highest available setting. Turn the valve on the R134a on. This will begin recharging the system.

Allow the R134a refrigerant to continue charging the system until the can is empty. You will notice the air within the vehicle getting increasingly cooler. Turn the engine off and remove the recharge hose from the low-pressure fitting. Close the hood of the Dakota. Repeat this process anytime the Dakota’s air conditioning unit needs coolant.

Items you will need

  • Owner’s manual

  • R134a refrigerant with connector hose

 How to Recharge an Air Conditioner on a 2000 Lincoln Continental

Remove the caps on the Schrader valves, used for charging on the high- and low-pressure refrigerant lines. These lines are located on the passenger's side fender well. The smaller of the two lines is the high-pressure line, and the larger of the two is the suction, or low-pressure line. The high pressure line will have a red cap and the low pressure line a blue cap.

Connect the refrigerant gauges to the system -- the blue hose to the larger, low-pressure line Schrader, and the red to the smaller, high-pressure line Shrader. Turn the knobs on each connector clockwise to open.

Connect the yellow hose from the gauges to the vacuum port on the top of the vacuum pump. Plug the vacuum pump in and turn it on.

Open both the blue and red valves on the gauges. Allow the system to evacuate until the blue, low-pressure gauge shows approximately 30 inches of vacuum. Notice that the dial has red numbers on the opposite side of the 0, in increments to 30 -- this represents the amount of vacuum in the system. When a proper vacuum is established, close the valves on the manifold gauges and shut off the vacuum pump. Watch the blue gauge vacuum reading for a minute or two, to see if it looses vacuum, indicating a leak in the system. If the gauge stays on 30 inches, there is no leak. If the needle drops off to 0, it has lost its vacuum, indicating a leak.

Repair the leak if the vacuum has dropped off. In order to do this you must go over every connection and check for tightness. If everything is tight, it is time to take the car to a shop to have it tested. The only way to test it further is to charge the system long enough to use a leak detector to locate the leak (or put leak detector dye into the system; the dye can be detected with ultra-violet light). The Freon must then be reclaimed in order to effect a repair. It is not only illegal, but also irresponsible to release fluorocarbons into the atmosphere.

Begin to vacuum the system again, now that it has been confirmed that there are no leaks. Turn the pump on, open the manifold valves and allow the system to remain in a vacuum for 30 minutes. Moisture evaporates much faster in a vacuum, so this will give the system enough time to purge itself of all moisture and air. The air must be removed because the system can't be charged as long as air is in the system. Two objects occupying the same space at the same time does not work.

Close the manifold valves on the gauges and shut off the vacuum pump. Remove the yellow hose from the pump. Connect the yellow gauge hose to a bottle of R-134. Open the valve on the can of Freon and loosen the yellow hose connection slightly next to the gauges to allow the air in the hose to leak out. When Freon mist begins to emerge from the loose hose connection, tighten the hose connection.

Charge the system by opening the blue, low-side valve only and allow the first can to discharge into the system. This will supply enough pressure to close the low-side switch to activate the compressor when the engine is started and the air turned on. When the can feels empty, close the blue, low-side valve. Remove the can and replace it with another full can. Bleed the air out again by opening the valve on the can and loosening the top yellow hose connector until Freon emerges. This is where an air conditioning system can be dangerous. Never, under any circumstances open the red, high-side valve when pressure is in the system. The can only has approximately 40 pounds of pressure, whereas the red, high-side line has 230 plus. This pressure will feed back immediately to the can and explode the can violently, causing bodily injury or death.

Start the engine and turn the air conditioning on, and the fan on high. Open the blue, low-side valve and watch the gauges. The system will be full when the low-side gauge shows approximately 30 PSI and the high-side red gauge shows 230 to 250 PSI. The gauge readings will vary slightly, according to the outside temperature. Watch the gauges for these numbers and place your hand on the accumulator. When the system is almost fully charged, you will feel the accumulator very suddenly drop in temperature to a chill. If this happens at 25 PSI on the low side and 210 PSI on the high side, continue until the pressures reach the prescribed range.

Close the blue, low-side valve and shut the engine off. Remove the hoses from the Shrader valves and install the caps on these valves.

Items you will need

  • Refrigerant gauges

  • R-134 Freon

  • Vacuum pump

 How to Recharge the Air Conditioning on a 2001 Pontiac Sunfire

Put on a pair of safety glasses. While this is a relatively simple task, you will be dealing with compressed gas.

Set up the recharging kit. Attach the gauge and hose to the R134a canister. You will need to screw the valve onto the top of the can but do not turn the valve all the way down. You will prematurely release coolant by doing so.

Open the hood of the vehicle and locate the aluminum air conditioning tubes. You will see two ports on the tubing, a high-side and low-side. Both will have dust caps on them. Remove the cap from the low-side port and attach the kit's hose. Do not attach the hose to the high-side port yet.

Place the recharging kit inside the engine compartment. Keep it away from any belts or components that will move when the engine is running.

Insert your key into the Sunfire's ignition and turn it on. Insert a thermometer into one of the vents and switch on the air conditioning full blast to the coldest setting. Let the engine reach operating temperature so that the air conditioning is at its lowest temperature.

Remove the thermometer from the vent and return to the engine compartment. Turn the valve at the top of the R134a canister all the way and release coolant into the air conditioning system. If you hear a gassy "rush" noise, it is only the coolant entering the system.

Turn off the valve at the top of the canister periodically and read the kit's gauges as the system recharges. You can tell if the system is recharged by touching the aluminum tubes. They will be completely cold. The system's normal operating temperature is 40 degrees Fahrenheit.

Turn the valve on top of the canister off once the canister is empty or the recharging is complete. Never overfill the system. Remove the hose from the low-side port and replace the dust cap. Close the hood. Turn the Sunfire's air conditioning and engine off.

Items you will need

  • 134a recharge kit

  • Thermometer

  • Safety glasses

 How Do I Recharge the Air Conditioning on a 2000 Chevy Cavalier?

Start the car and allow the engine to reach operating temperature.

Set the air conditioning to “Max A/C” and place the blower fan speed control on its fastest setting.

Unscrew the blue low-pressure port cap. It is located to the left of the A/C compressor, on top of the large diameter aluminum refrigerant line.

Attach the in-line pressure gauge to the refrigerant canister. Connect the other end of the pressure gauge hose to the low-pressure port.

Note the pressure reading on the gauge.

Turn the refrigerant canister upside-down. Slowly rotate the refrigerant release valve on the in-line pressure gauge until it pierces the seal on the canister. Watch the pressure gauge for increasing pressure in the system. Rotate the release valve in the opposite direction to stop the flow of refrigerant when the pressure gauge reads 45 psi.

Disconnect the in-line pressure gauge from the low-pressure port. Replace the port cap. Verify that the system is producing cool air.

Items you will need

  • In-line refrigerant pressure gauge

  • R-134a refrigerant canister

 How to Recharge the Air Conditioner in a 1997 Chevy Cargo Van

Put the Chevy Cargo Van into park on a level area. Allow the van to sit for about 30 minutes to ensure all components have cooled down.

Open the hood of the Chevy Cargo van and locate the air conditioning unit low-pressure hose fitting. The low-pressure hose is the hose that runs from the accumulator to the compressor. If you are unsure of these components, the owner's manual has a diagram.

Assemble the R134a recharge kit by attaching the recharge hose to the valve on the top of the can. The recharge hose will snap onto the valve, securing it in place.

Turn the can of R134a on by turning the valve to "on." Connect the R134a recharge hose to the low-pressure fitting on the air conditioner unit. Be sure to hold the can upright for maximum flow.

Turn the ignition key to turn the engine on. Place the air conditioner on the highest setting. This will begin the recharge process; continue to charge the system until the can of R134a is completely empty.

Turn the engine off and remove the key from the ignition. Turn the R134a valve to the "off" position and disconnect the hose from the low-pressure fitting. Close the hood of the Chevy Cargo van.

Items you will need

  • Owner's manual

  • R134a refrigerant kit

 How to Recharge the Air Conditioner on a 1997 Honda Civic

Assemble the recharge kit according to its instructions. Turn the tap valve to the full and open position. Screw the valve on the can so it is "hand tight," making sure the seal or O ring inside the threaded portion has formed an effective seal.

Remove the dust cover from the low-side charging port (at the compressor) and attach the hose quick-connect fitting to the charging port. The hose connector will only fit the low-side port; do not attempt to install it on the high-pressure port.

Start the engine and turn on the air conditioning system. Check that the compressor is running (it must be running for the system to recharge). Turn the air conditioning to the highest setting and open the car doors, if necessary, to keep the compressor operating.

Turn the tap valve to the closed position to puncture the refrigerant can. Then open the valve completely (you should hear the refrigerant flow). Hold the can upright and shake it occasionally while the refrigerant is flowing. Periodically turn off the tap valve and check the temperature of the air conditioner. It should be 30 to 40 degrees cooler than the outside air. If available, use a thermometer to measure the temperature.

Turn off the refrigerant flow when the desired air temperature is reached or the can is empty. Disconnect the hose and replace the dust cover.

Items you will need

  • R-134a recharge kit

  • Extra can of R-134a refrigerant (optional)

  • Thermometer (optional)

 How to Recharge the Air Conditioning in a 2003 Ford Focus 2.0

Attach the A/C gauge set to the high and low pressure service ports on the Focus. These ports are located under the cowl on the passenger side of the fire wall. They are different sizes, and the quick-disconnect fittings on the gauge set will only attach to the correct size. Pull back on the lock ring on the gauge fitting and snap the fitting onto the port. Turn the knobs on the fittings to open the service ports.

Attach the yellow hose on the center of the gauge set to the vacuum pump. Plug the vacuum pump into an electrical outlet and switch it on. Open both valves on the gauge set by turning them counterclockwise. Allow the vacuum pump to run for one hour. During this time, any moisture in the system will vaporize and be pulled from the system by the pump.

Close the valves on the gauge set and turn off the vacuum pump. Unscrew the yellow hose from the pump. Attach the can tap supplied with the gauge set to the yellow hose. Screw a can of refrigerant into the tap and turn the knob on the tap all the way in and out to open the can.

Start the engine and turn on the air conditioning. Open the blue valve on the gauge set to add refrigerant to the system. The system is full when the blue gauge reads 35 to 40 PSI and the red gauge reads 300 to 400 PSI.

Close the blue valve on the gauge set and turn the engine off. Wait for a few minutes until the pressures on the gauges stabilize. Disconnect the hoses from the air conditioning system by pulling back on the locking rings on the fittings until they pop off the ports.

Items you will need

  • R-134A gauge set

  • Vacuum pump

  • R-134A refrigerant

 How to Recharge the Air Conditioner in a PT Cruiser

Locate the air conditioner (A/C) controls in the center dash console in the PT Cruiser. From left to right, set the controls to Medium A/C blower speed, Bi-level vent output, maximum A/C and recirculating air. This will provide the coldest temperatures from the system.

Attach the A/C gauge-set hoses to the service ports located on the A/C lines under the hood. In the PT Cruiser, both the low- and high-pressure service ports are located on the aluminum A/C lines on the passenger side of the engine compartment. Pull back on the locking rings on the quick disconnect fittings on the ends of the A/C gauge hoses and snap the fittings onto the service ports. They are different sizes and cannot be installed improperly.

Close both valves on the face of the A/C gauge set. Twist the knobs on the high- and low-pressure hose fittings clockwise to open the service ports on the A/C lines. Screw the fitting on the end of the yellow service hose on the A/C gauge set onto the inlet fitting of the vacuum pump.

Plug the vacuum pump into an electrical outlet and turn the power switch on. Open both valves on the face of the gauge set and allow the pump to run for an hour to remove moisture from the system.

Close both valves on the gauge set and turn the pump off. Unscrew the yellow hose from the pump and screw it to a can tap. Screw a can of refrigerant into the can tap and open the can using the thumbscrew on the tap. Open the blue low-pressure valve on the gauge-set face to allow the refrigerant to flow into the PT Cruiser's A/C lines.

Start the engine and monitor the pressure indicated on the gauges. When they stabilize, close the valve on the gauge face. Unscrew the empty can of refrigerant and screw a full can into the tap. Open the can and install the second can in the same manner as the first. The PT Cruiser holds 18 ounces of refrigerant, which is a little more than 1-1/2 cans of refrigerant.

Items you will need

  • Vacuum pump

  • A/C gauges

  • R-134a refrigerant with oil dye

 How to Recharge the Air Conditioning in a Ford Mustang

Insert a can of 134A freon into the bottom of the home freon recharge kit valve by screwing it onto the base clockwise. The interior needle of the valve will puncture the can and pressurize the valve. Some valves have optional gauges that will show this pressure. The can should be seated firmly into the valve and not be making any hissing sounds that would indicate a leak.

Locate the low pressure side charge nipple of the air conditioning system located near the evaporator canister. On R-12 freon systems, this nipple could be mounted on a line and may require a nipple adapter. The nipple adapter comes in most 134A conversion kits and is simply an attachment that changes the nipple to the correct size for the home valve kit. The valve will have a hose and connector nozzle. Pull the ring of the connector back and press it onto the charge nipple of the system. Let go of the ring and it should lock the hose to the nipple.

Start the Mustang and turn on the air conditioning system to the maximum setting.

Pull the trigger on the valve (or turn the valve counterclockwise on older kits) and allow the air conditioning system to vacuum in all of the freon, emptying the can. The can will be empty in about five minutes, but keep it upright and do not shake it.

Disconnect the hose from the low pressure nipple and unscrew the can counterclockwise to release it from the valve. Replace it with a can of lubricant (optional), a can of UV dye (optional) or another can of freon. Continue to add freon into the system until it does not vacuum in any more. The average amount of freon a Ford Mustang can hold is about two pounds, or two cans' worth.

Disconnect the hose from the system, shut the car off and listen for leaks. When the system is fully charged, it will have the highest pressure, and leaks will be stronger.

Items you will need

  • 2 cans of 134A freon coolant

  • Home recharge kit (valve and trigger)

  • Can of lubricant (optional)

  • Can of ultraviolet dye (optional)

 How to Recharge the Air Conditioning on a 1995 Ford Mustang

Attach the gauge set hoses to the service ports in the engine compartment. On the 1995 Ford Mustang, the high-pressure service port is in the front of the engine compartment on the passenger side, between the air cleaner housing and the upper radiator hose. The low-pressure service port is located on the driver's side of the engine compartment between the intake manifold and the oil dipstick. Pull back the lock ring on the hose end and snap the end onto the port. Turn the knob on the hose end clockwise to open the port.

Screw the service hose end (the center hose on the gauge set) to the vacuum pump's inlet. Plug the pump's electrical plug into a wall socket and turn the switch to the "On" position to start the pump. Open both valves on the front of the gauge set and allow the vacuum pump to run for one hour. This will remove all moisture from the system and provide the best cooling capacity.

Close both valves on the front of the gauge set and turn off the vacuum pump. Unscrew the service hose from the pump and screw it onto the can tap. Screw a can of R-134a refrigerant onto the can tap and twist the thumbscrew on the tap all the way into the can. Unscrew the thumbscrew all the way and open the blue (low-pressure) valve on the gauge set, located below the low pressure gauge. Refrigerant will begin to flow into the system.

Start the engine and set the A/C controls on the dash to maximum cooling and medium or low fan speed. Monitor the gauges while the refrigerant is being recharged. When the gauge pressures stabilize, close the service valve (the blue valve) and unscrew the empty can of refrigerant from the can tap. Inject additional cans of refrigerant in the same manner as the first can. The 1995 Ford Mustang holds 2.2 pounds (about three cans) of R-134a refrigerant.

Turn off the engine and close the service valve on the gauge face. Unscrew the knobs on the hose ends and pull back on their locking rings to disconnect them from the ports. Close the hood and test drive the Mustang for about 10 minutes to verify that the air conditioning system is cooling properly.

Items you will need

  • A/C gauge set

  • Vacuum pump

  • Can tap