How to Recharge the A/C in Cars

by Contributing Writer; Updated June 12, 2017

Over time, small amounts of refrigerant can leak out of the air conditioning system in your Dodge car truck. This, along with the occasional air-conditioning repair that is done, will require the system to be recharged. Recharging a completely empty system will require the system to be evacuated of any moisture. Use a vacuum pump to pull a vacuum on the system and remove the moisture. Simply topping off the system may not require this, but it is good to know how to do it anyway.

Under The Hood:

 How to Recharge the A/C in a Dodge Ram

Install the A/C gauge set by locating the service ports located on the lines. Attach the blue hose of the set to the low-pressure side and the red hose of the set to the high-pressure side. The low-pressure fitting is located on the accumulator near the passenger side of the firewall, and the high-pressure fitting is located on the line connecting the condenser (located in front of the radiator) to the evaporator (located behind the firewall in the passenger compartment).

Attach the yellow service hose of the gauge set to the vacuum pump if you are going to pull a vacuum on the system to remove moisture. The system must be completely empty to do this to avoid damage to the pump. If you are simply topping the system off, skip this step and go to Step 3. Turn the pump on and open the service valves on the gauge set. Allow the vacuum pump to run for one hour to ensure all moisture has been removed from the system.

Close the service valves on the gauge set and disconnect the vacuum pump. Attach the can tap that came with your gauge set and attach a can of refrigerant to the tap. Turn the thumbscrew on the can tap all the way in and all of the way out to open the can. Open the blue, low-pressure side, service valve on the gauge set, and allow refrigerant into the system. Start the engine and set the air-conditioning controls to maximum A/C. When the first can is empty, close the service valve and attach another can. Continue this until the required amount of refrigerant has been added.

Turn off the engine and allow the pressures displayed on the gauge set to equalize. Remove the hoses from the service ports and replace any caps that were on the service ports.

Items you will need

  • A/C gauge set

  • Vacuum pump

  • Refrigerant

 How to Recharge the AC on a 1994 Jeep

Set the Jeep's parking brake. Move the shifter into neutral (manual trans) or park (automatic). The recharging process is done with the engine running, so these are basic safety precautions.

Release the hood and prop it open. Within the engine, look for the air conditioner's aluminum tubes. They should be toward the center. You will also notice two pressure connections on the pipes. The one toward the back of the engine is called the high-side port, the one toward the front is the low-side port. The R134a recharging kit will be connected to the low-side port.

Set the recharging kit down in a safe, secure spot. It needs to be away from anything that will move or shift it, once the engine is running. This means any belts or fans could pose a hazard. Leave the kit and get behind the Jeep's steering wheel.

Turn the engine on and watch the thermostat on the Jeep's instrument cluster. Once the engine has warmed up, turn the air conditioning on to its lowest temperature setting. Switch the air conditioner's blower on high.

Put on the safety glasses and the gloves. Return to the engine and the recharging kit. Turn the nozzle atop the can and let the R134a freon flow into the system for one minute. Turn the flow off and let the system rest for a minute. These rest periods will allow the air conditioner to stabilize and circulate the freon as you add it.

Place a thermometer in the Jeep's central air conditioning duct. Monitor the thermometer's readings as you add freon. At its coldest setting, a fully charged air conditioner will cool air to 40 degrees. In hot weather, a charged system will level out anywhere between 40 and 60 degrees. Once the thermometer readings stop falling, the system will be charged.

Remove the thermometer from the air conditioning duct. Detach the recharging kit from the low-side connection. Close the hood, but let the Jeep run for 10 minutes after the process is complete. The running air conditioner will evenly distribute the freon throughout the system. Turn the air conditioner and the engine off.

Store the recharging kit upright in a dark area. Do not take the components apart or release the leftover freon as a means to get rid of it. You can use the leftover R134a later.

Items you will need

  • Safety glasses

  • Gloves

  • R134a recharging kit

 How to Recharge the AC in a Chevy Truck

Attach the hoses from the gauge set to the service ports on the Chevy truck. The service ports are located on top of the compressor on trucks made after 2001. Trucks made before 2001 have the ports on the accumulator and high pressure hose. The ports are different sizes, so you can't install them incorrectly. However, early models that use R-12 refrigerant require an adapter to fit the hose to the high-pressure service port.

Attach the vacuum pump to the center hose of the AC gauge set. Plug the pump's power cable into a 110-volt outlet and turn it on. Open both valves on the front of the gauge set. Allow the pump to run for one hour to remove all the moisture in the system.

Close the valves on the gauge set and turn off the pump. The vacuum reading on the gauge set should hold steady for 15 minutes. If the gauge set shows that the vacuum has leaked off during this time, there is a leak in the system.

Disconnect the vacuum pump from the gauge hose and install a can tap on the hose. Slip a can of refrigerant into the tap and open it by screwing in the thumbscrew. Unscrew the thumbscrew and open the blue valve on the gauge set. Allow half of the can of refrigerant to flow into the system.

Start the engine and turn on the AC. When the can is empty, close the gauge valve and remove the can. Attach another can to the tap and open the blue gauge valve. Repeat until you have installed 2.0 lbs of refrigerant in the system.

Close the gauge valve and disconnect the gauge set from the truck. Test drive the Chevy to verify that the system works properly.

Items you will need

  • AC gauge set

  • Vacuum pump

  • Can tap

 How to Recharge the A/C on a 1997 Nissan Maxima

Locate the low side port of the air conditioning system. It is near the passenger side strut tower on one of the refrigerant lines. The port is covered by a cap marked "L."

Turn on the air conditioning to the maximum setting.

Screw the hose end of the recharge hose onto the low side port.

Place the tap end of the valve onto the top of the refrigerant can. Turn the valve clockwise to pierce the top of the can. Release the valve by turning counterclockwise and refrigerant will run from the can into the system. Keep the can upright, shaking it occasionally.

Place the thermometer in the center air conditioning vent inside the vehicle. The temperature of a correctly functioning air conditioning is approximately 30 to 40 degrees Fahrenheit. If the temperature is still above this level, add another 12-ounce can of refrigerant. Never add more than two cans of 12-ounce refrigerant.

Turn the valve on the hose clockwise to seal off the can of refrigerant when finished. Unscrew the other end of the hose from the low end port. Replace the cap on the low end port.

Items you will need

  • 12 oz. can of R-134a refrigerant

  • Air conditioning recharge hose

  • Thermometer

 How to Recharge the AC on a Honda Passport

Attach the A/C gauges to the service ports in your Honda passport. The blue hose attaches to the service port located on the low-pressure line located between the firewall and the compressor. The red hose attaches to the high-pressure service port located on the high-pressure line between the firewall and the condenser located in front of the radiator.

Close the valves on the A/C gauge set and attach a can of refrigerant to the can tap on the yellow service hose of the gauge set. Turn the thumbscrew all the way in and all the way out to open the can.

Start the engine, then turn the A/C controls to max A/C, recirculating air and medium blower speed. Open the blue valve on the gauge set to allow refrigerant to enter the system. When the pressure readings on the gauge set reach 35 psi on the low-pressure side and 300 on the high-pressure side, the system is full.

Turn off the engine and remove the gauge set from the vehicle. Place a thermometer into the middle vent on the dash and allow a few minutes for the temperature to stabilize. If the difference between the inside temperature and outside temperature is 40 degrees or more, the system is functioning properly.

Items you will need

  • A/C gauges

  • Thermometer

  • Refrigerant

 How to Recharge the AC on a 1999 Honda Accord

Evacuate the air conditioning coolant from the system. With coolant leaking from the system, debris and contaminates can be in the lines and compressor. Evacuating the coolant from the system removes debris and contaminates.Take the Accord to a garage or oil change facility to evacuate the system. They will remove the coolant with professional equipment.

Attach the can of 134a coolant to the valve that is included with the recharge kit by turning it clockwise onto the bottom of the valve body. The needle inside the valve will puncture the top of the can, pressurizing the valve.

Attach the nozzle of the valve unit to the low pressure side of the Accord's air conditioning lines. This is near the evaporator, on the passenger side of the engine compartment. The nozzle presses to the low pressure nipple and catches it, locking them together.

Start the engine and set the air conditioner to its maximum setting. Open the valve and allow the coolant to be sucked into the system. This usually takes about ten minutes. Don't shake or turn the can, simply allow it to empty while upright. Once the coolant in the can has been dispensed, pull the nozzle from the low pressure port by pulling up on its outer ring while simultaneously pulling the nozzle. Turn the can of coolant counterclockwise and dispose of it.

Repeat Step 4, using the can of compressor lubricant. This lubricant can already be added to the coolant, but typically they are separate. Allow the can to empty, then remove it as before. Continue this process with more coolant until the system does not take in any more. Accord air conditioning systems use about two cans of coolant and a can of lubricant.

Items you will need

  • Coolant (freon) recharge kit

  • Compressor oil (one can)

  • Two cans of 134a coolant (if not supplied in the kit)

 How to Recharge the AC on a Chrysler Pacifica

Move the Pacifica to flat ground, if you plan on charging the system some place other than your personal garage. Engage the emergency brake, and put the Pacifica's gear shifter into neutral or park. Lastly, before starting the recharging process, open all the doors.

Locate a set of metal pipes within the Pacifica's engine. Specifically, you are looking for large diameter aluminum tubes between the automobile's compressor and drier. There, you will find the Pacifica's low side connector. Remove the connector's cap.

Attach your refrigerant's recharging kit to the low side connection. The kit features a service hose that will directly onto the port. Put the kit down, but not anywhere near engine parts that will shift once the engine is running.

Move to the Pacifica's driver's seat. Start the engine and let it completely warm up. Switch on the air conditioner to its coldest setting and its hardest air-blowing capacity.

Return to the Pacifica's engine and the recharging kit. Turn down the handle atop the kit's freon container. This will break the container's seal and send freon through the kit's hose and into the air conditioner. You will heard "rushing" noises. This is normal and not a cause for worry.

Charge the Pacifica's air conditioner for a minute. Then, turn the handle atop the refrigerant container upwards. This will cut off the flow of Freon. Let the system charge for one minute. Freon will circulate through the system quicker this way.

Add more Freon incrementally and in one minute intervals. Keep an eye on the refrigerant kit's pressure gauge. Place a thermometer into the Pacifica's center air conditioning duct.

Monitor the thermometer's temperature readings. Once the system drops to 40 degrees, the system is charged. Outside weather may have an influence. If you are charging the system during sweltering summer months, the final stopping point will be somewhere between 40 and 60 degrees. Stop charging the system whenever the temperature levels off.

Pull the thermometer from the central duct. Cut off the flow of Freon and remove the kit from the low side connection. Let the system, as a whole, further stabilize for another ten minutes, before you shut off the Pacifica's air conditioner and engine.

Items you will need

  • Freon recharging kit

  • Thermometer

 How to Recharge the AC in a Grand Vitara

Open and support the hood of your Grand Vitara. Locate the AC compressor. One of the devices connected to the accessory belt, the compressor sits toward the front of the engine at the bottom of the bay. Find the lines exiting the compressor, and follow the one that goes toward the top of the engine bay until you find a hookup, which somewhat resembles a large tire stem.

Push the connector of an R-134a A/C recharge device onto the hookup you just found. It will simply slide into place once you pull back on the quick-connect fitting.

Start the engine, turn the AC on high, and check to ensure the Suzuki is in park. The pressure gauge on the device will now indicate the level of refrigerant currently in the system. If the needle points anywhere below the green area of the gauge, the pressure has dropped too low and the Grand Vitara's system needs a recharge.

Hold down the trigger on the recharge device. The pressure gauge will begin to rise as refrigerant enters the system. Continue depressing the trigger until the needle reaches the middle of the green zone. Do not overcharge the system by adding too much refrigerant, since you cannot remove it easily.

Turn off the engine. Disconnect the recharge device by reversing the process used to attach it. Take a drive to test the performance of the freshly charged air conditioner.

Items you will need

  • R-134a recharge device

About the Author

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