How to Charge the Air Conditioner on Vehicles

by Contributing Writer; Updated June 12, 2017

If your Vehicles is having air-conditioning issues, you may be able to recharge it without having to take it to a mechanic's shop. The caveat Vehicles recharging the air-conditioning system yourself is that the Vehicles needs to have some cold air coming out of the vents, which means that there is still some refrigerant left in the system. It should be noted that recharging the refrigerant involves the use of chemicals that are dangerous to your body and the environment, which is why the Environmental Protection Agency closely regulates the use of certain refrigerants.

Under The Hood:

 How to Charge the Air Conditioner on a '99 Ford Expedition

Raise and support the hood. With the engine turned off, locate the metal air conditioning line, which runs sideways along the very back of the Expedition's engine bay. There is a service port on top of the tube covered by a black plastic cap. Remove this cap.

Screw the hose of a R-134a recharge system onto the service port. Start the engine and turn the air conditioning to its highest setting. Return to the engine bay to check the pressure gauge on the recharge system. If the gauge indicates the pressure is beneath the green-colored area, the coolant levels are too low and the system will benefit from a recharge.

Hold down the trigger on the recharge system for several seconds at a time, then pause to check the gauge again. Continue this process until the needle is in at least the middle of the green section.

Turn off the engine, detach the hose and replace the cap on the service port. If the canister does not appear to be empty, you can save it for future use.

Items you will need

  • R-134a all-in-one recharge kit

 How to Charge the Air Conditioner for a Ford Taurus

Remove the Schrader valve cap from the low side line. A vehicle can be charged only from the low side of the air conditioning system. The low side averages between 20 to 40 pounds of pressure and the high side carries an average of 200 to 275 pounds of pressure. If the Freon bottle is hooked up to the high side, the pressure in the high side can exceed the pressure within the canister and it can grenade (blow up violently). The low side is the return line from the evaporator, also known as the suction side. It is always the largest line coming off the compressor. The high side is the line that carries the pressure from the compressor to the condenser and from the condenser to the evaporator inlet. This is the smallest, thinnest line.

Attach the hose from the singular unit to the low side fitting. If you are using gauges, attach the blue line on the gauges to the low side fitting. Attach the red line of the gauges to the high side fitting on the small line. Make sure the valves are off.

Install the Freon canister and turn the valve on. If gauges are being used, loosen the yellow line from the Freon canister at the gauge enough to allow the air out and then retighten.

Start the vehicle and make sure that the air conditioning is on and the fan is working. If the compressor does not come on it is because the Freon level or pressure is too low to turn the low-pressure sensor on. The compressor should come on as the pressure is increased with the addition of Freon. If it does not, then there are other issues. When the compressor comes on, the fan should come on. If it does not, shut the air conditioning off and fix the fan. If the fan does not operate, the head pressure will rise too high and the air conditioning system will not function.

Open the valve on the canister or, if using gauges, open the valve on the low blue side of the gauges. Feel the low-side line while it is charging and as soon as it flashes or gets ice cold, stop charging. If you ar using gauges, when the low-side pressure reaches 25 pounds and the high-side pressure reaches 225 to 250 pounds, it is done charging. Remove the filler hoses and cap the fittings.

Items you will need

  • Freon

  • Air conditioning gauges or refill kit

 How to Charge an Air Conditioner in a 2000 Ford Explorer

Turn the Ford Explorer off and allow the vehicle to sit and cool for 30 minutes. This gives the components under the hood enough time to cool off, preventing any burns.

Open the hood of the Ford using the hood release lever located on the driver's side of the vehicle, under the steering column.

Locate the air conditioner low-side service fitting. The low-side service fitting can be found on the suction hose connecting the accumulator to the compressor. Refer to the owner's manual for a diagram if needed.

Assemble the R134a recharge kit by attaching the recharge hose to the valve on top of the can. Turn the valve clockwise to puncture the top of the can, allowing vapors to be released. Close the can to prevent loss of extra refrigerant.

Connect the R134a recharge hose to the low-side fitting under the hood. Start the engine of the Explorer. Turn the can of R134a to the "On" position to begin the recharge process.

Allow the refrigerant to recharge the system until the can of R134a is empty. Turn the valve counterclockwise to the "Off" position and disconnect the hose from the low-side fitting. Close the hood and your air conditioner is now ready for use.

Items you will need

  • Owner's manual

  • R134a refrigerant

 How to Charge the Air Conditioner on a 1994 Oldsmobile Cutlass

Open the Oldsmobile's engine compartment and search for the air conditioner's pipes. They are made of aluminum, and they will feature two capped, pressurized connection ports. The high side connection port is meant for maintaining air conditioning system pressure. It is not used in this task, so ignore it. Regardless, you will not be able to attach the kit to this connection port.

Slip the cap off of the low side connection port. Fit your R134a kit's servicing hose to this low side connection port. Set the kit down, but be cautious of where you put it. Since you will run the Oldsmobile's engine later, the kit cannot be near anything that will move, like engine belts.

Start the Oldsmobile's engine. Allow the engine to sit and idle unto it has warmed to its usual operational temperature.

Blast the air conditioner. The system needs to be set to the lowest air temperature and the hardest blowing force. These are necessary precautions. Later, you will need to take the system's internal temperature, and any R134a refrigerant you add will need to circulate within the system.

Open all of the Oldsmobile's doors. You do not want air within the car's passenger compartment to build up and accidentally switch the sytem off while recharging is underway.

Pick up the R134a recharging kit. Twist the kit's nozzle all the way down. This will release the R134a refrigerant through the servicing hose and into the system's aluminum pipes. You will hear "rushing" sounds. That would be perfectly normal.

Place a thermometer into the Oldsmobile's central air conditioning duct.

Charge the air conditioning system incrementally. After a minute, close the kit's connection with the system by twisting the nozzle upwards. Keep an eye on the kit's pressure gauges. The air moving within the system will distribute the new refrigerant, stabilizing the system. After a minute of "rest," add another charge. Repeat until the system is charged.

Monitor the thermometer in the Oldsmobile's central air conditioning duct. The system is charged once the thermometer reads 40 degrees. If the outside weather is hot, and your home's garage is not air conditioned itself, the final operational temperature within the system could be anywhere between 40 and 60 degrees.

Remove the thermometer. Detach your R134a kit from the low side connection port. Let the engine and air conditioning run for an additional 10 minutes. This will ensure that the R134a refrigerant fully circulates through all of the air conditioner's components. Turn the engine and air conditioning off, afterwards

Items you will need

  • R134a refrigerant kit

  • Glasses

  • Goggles

  • Thermometer

 How to Charge an Air Conditioner in a Mitsubishi Mirage

Raise the hood on the Mirage and prop it open. Find the high and low service fitting valves for the air-conditioning system, which should be located near the upper left part of the engine. Since the mid-1990's, the fitting valves for R134A refrigerant use two different sized valves for recharging, sized at 13 and 16 millimeters. Look for the low side fitting near the hose that connects the accumulator and the compressor. The high side fitting is on the other side of the compressor, near the hose that connects to the condenser.

Check the Mirage owner's manual to ascertain the correct refrigerant pressure, which can vary among different manufacturing years. Otherwise, fill the system until the low-pressure gauge measures between 25 and 40 pounds per square inch, or psi.

Attach the service hose valve from the recharge kit to the refrigerant can. Rotate and tighten the valve and hose connection until the can is punctured. Turn the valve slightly in the opposite direction to loosen it so that the air is bled from the hose. Shut off the valve once the air is bled from the hose and refrigerant can.

Hold the refrigerant can upright, placing it near the low service fitting on the Mirage's air-conditioning system. Screw the recharging kit's hose onto the low service fitting. Screw the high-pressure gauge from the recharge kit onto the high-pressure service fitting. If your kit has a high-pressure gauge, it should read between 225 and 250 psi when your Mirage's air conditioning system is fully recharged.

Turn on the engine and turn the air conditioning on full blast. Open the valve on the recharge kit so refrigerant is pulled into the vehicle's air-conditioning system. It is useful to have a friend inside the vehicle monitoring the temperature of the air coming from the Mirage's vents. Wait for five to 10 minutes to allow the air conditioning to be fully recharged. Continue to monitor the low-pressure gauge on the recharge kit.

Turn off the valve on the recharge kit and remove it from the air-conditioning system's fitting valves.

Items you will need

  • Refrigerant recharging chemicals (R134A)

  • Refrigerant recharge kit with gauge

 How to Charge the AC in a Mercedes Benz

Visit an auto parts store and purchase a Refrigerant Kit consisting of a canister of 134a refrigerant, a pressure gauge and a connection hose with a coupler.

Turn on the vehicle's engine and set the air conditioning system to maximum cool. Open the hood of your vehicle and locate the low-pressure service port on the larger-diameter aluminum tubing next to the engine on the driver's side.

Remove the protective cap from the low pressure service port, attach the Refrigerant Kit hose and gauge to the service port using the coupler at the end of the hose, and read the pressure in your air conditioning system. A low-pressure gauge reading is in the green range, and a normal reading is in the blue range. Pressure readings in the yellow and red ranges are too high.

Charge the air conditioning system if the refrigerant level is low. Shake the refrigerant canister well, securely tighten the charging hose to the refrigerant canister, and connect the charging hose to the low-pressure service port. Press down the button on top of the refrigerant canister to begin charging. The canister should should be held upright and shaken or agitated every two or three seconds.

Stop recharging the system once the pressure gauge readings reach the normal range (blue). Detach the connection hose from the low-pressure service port, replace the cap, and close the hood.

 How to Charge the A/C in a Ford Focus

Consult the owner's manual to locate the area where the service fittings lie on the vehicle's A/C. This location varies depending on the model of Ford Focus you own, which is why you must consult the owner's manual for exact details. You can locate the high-side fitting on the hose that goes from the compressor to the condenser. The opposite fitting is located on the suction hose that runs from the accumulator to the compressor.

Attach the charging hose to the coolant can.

Turn the can's valve. This places a hole on the top of the can to let out a tiny portion of air and refrigerant. When you finish, close the valve and attach the service hose to the side fitting on the bottom.

Start the car engine and place the car's A/C fan at its strongest level. Turn the valve of the coolant can to let its contents into the A/C unit. Repeat this step until the air blowing from the vents feels cold and the vehicle interior is sufficiently cooled.

Items you will need

  • R134a coolant

 How to Charge the AC on a 1999 Ford Escort

Turn the valve counterclockwise on the R-134a automotive recharge kit to open the valve. Attach a container of R-134a refrigerant to the kit.

Open the hood, and locate the low-pressure port on the air conditioning system. The port will be close to the firewall on the passenger side of the engine compartment. Remove the plastic cap from the port by turning it counterclockwise with your fingers.

Connect the recharge kit hose to the low-pressure port. Pull back on the hose adapter slightly, and slip the hose over the port. Release the hose adapter, and it should lock in place.

Start the engine, and turn on the air conditioner. Set the air conditioner to the maximum cool setting, and set the fan blower to high.

Turn the valve clockwise on the R-134a automotive recharge kit to close the valve, and break the seal on the R-134a refrigerant. Once the valve is closed completely, turn it counterclockwise all the way to allow the refrigerant to flow into the vehicle system. Add the entire container of refrigerant to the vehicle.

Check the air temperature flowing through the vents in the passenger cabin with a thermometer. The air should be 35 to 40 degrees colder than the outside temperature. If necessary, use another can of R-134a refrigerant to achieve the desired temperature.

Turn off the engine. Pull back on the hose adapter slightly, and remove the recharge kit hose from the fill port. Replace the cap by turning it clockwise. Close the hood.

Items you will need

  • Safety glasses

  • Thermometer

  • R-134a refrigerant

  • R-134a automotive recharge kit

 How to Charge the A/C in the 2005 Jeep Liberty

Soak a clean towel in very warm water. You may need it later. Also, put on protective eyewear. While adding R134a to a Jeep's A/C system is a relatively simple task, you are still dealing with a compressed gas.

Open the recharging kit's packaging and assemble the kit. The hose, gauge and valve assembly will need to be screwed into the top of the R134a's canister. Do not turn the valve all the way to the base, however. That will release the R134a too early.

Open the 2005 Jeep Liberty's hood and locate the A/C system. You are looking for aluminum tubing with a high- and low-side port. Remove the cover from the low-side port and place the cover in a safe spot for later. Fit the recharging hose snugly and securely onto the low-side port.

Locate a safe place inside the engine compartment to set the recharging kit. Step 5 requires starting the Jeep Liberty's engine, so the kit needs to go somewhere away from parts and components that will move. Set the kit down.

Climb behind the 2005 Jeep Liberty's steering wheel. Place the key into the ignition and crank the engine. Switch on the A/C system to maximum coldness and blowing capacity. Place a thermometer into an A/C vent and watch the temperature drop. Once the A/C has reached its coldest possible temperature, look at the temperature gauge on the dash. The vehicle needs to be at its normal running temperature.

Return to the recharging kit, and take the thermometer with you. Leave the doors open so that the A/C system will not accidentally cycle "off."

Pick up the recharging kit you left in the engine compartment. Turn the valve at the top of the R134a canister all the way down. The R134a freon will rush out of the canister and into Jeep's A/C system. If the can gets too cold to hold, you can wrap it in a wet, warm towel.

Turn the valve atop the canister upwards and stop the flow of freon. This will let you monitor the gauges on the recharging kit. Allow a minute, at least, for the new gas charge to work into the A/C system.

Place a thermometer into one of the A/C's ducts and monitor the temperature inside the system. Once the output temperature has dropped to 40 degrees, the system has reached its normal operational coldness. Also, toward the end of the process, all the aluminum tubing will be cold.

Close the valve atop the R134a canister once the recharging is complete or when the can has become depleted. Never over-charge or overfill an A/C system. It is always best to err on the side of not topping off the system completely. Remove the recharging hose from the low side port and replace the covering. Close the hood and shut the 2005 Jeep Liberty's engine and A/C system off.

Leave the hose, gauge, and valve atop the R134a canister if there is any refrigerant left. Do not discharge the excess freon. Store the can in a dark place away from fluctuations in temperature and in an upright position.

Items you will need

  • Thermometer

  • Protective eye coverings

  • R134a recharging kit

 How to Charge the AC in a Nissan Frontier

Park the car on flat ground. Guard against a rolling hazard by activating the Nissan's emergency brake.

Assemble your Freon recharging kit, if it was sold with the parts unattached. Attach the servicing hose and gauge to the can of Freon.

Open the Nissan's hood and find the air conditioning unit. Specifically, you are looking for two pressurized service connectors on a series of aluminum pipes. The higher side connector can be left alone, as it does not play a role in this task. Pull the cover off of the lower side connector and fit your Freon kit to it. Set the kit down in a stationary, safe place on top of the engine.

Open all of the Nissan's doors and then take a seat behind the steering wheel. Slide your key into the igntion and start the engine. Let the engine warm up.

Turn on the air conditioning unit and set it to the coolest temperature. Set the air conditioner's blower to its highest level.

Position a thermometer in the Nissan's central air conditioning duct.

Open the Freon canister by twisting the kit's handle all the way down. Let a minute's worth of Freon charge into the air conditioning unit's pipes.

Close the Freon canister by twisting the kit's handle up. This will give the Nissan Frontier's air conditioner a chance to evenly move the new Freon around the entire system. Continue to add Freon incrementally.

Monitor the thermometer in the air conditioning duct as you charge the system. The air temperature within the Nissan Frontier's air conditioning will drop during the charging process. When the system is fully charged, the thermometer will read 40 degrees. There is, however, one exception to consider. If you are outside during very hot weather, the thermometer my not read 40 degrees. In this case, the system's temperature will plateau somewhere between 40 and 60 degrees.

Remove the Freon recharging kit from the lower side connector. Let the new Freon circulate through the system for 10 minutes. Turn off the Nissan's air conditioner and engine to complete the process.

Items you will need

  • Freon recharging kit

  • Thermometer

  • Gloves

  • Glasses

 How to Charge an AC in a 2000 Chevy Malibu

Attach the blue and red hoses from the gauge set to the service ports in the engine compartment. The blue hose goes to the low-pressure port located in the front of the engine compartment near the top of the radiator. The red hose attaches to the high-pressure fitting located under the air filter housing on the driver side of the engine compartment.

Start the engine and set the air conditioner controls to high fan speed and maximum air conditioning. Allow the engine to run for a few minutes with the doors closed and windows up to stabilize the pressures.

Attach a can of refrigerant to the can tap on the end of the yellow hose and turn the knob on the tap to open the can of refrigerant. With the engine running and the A/C on, open the blue valve on the gauge set. This will allow the refrigerant in the can to enter the system.

Close the blue valve and read the pressures when the can is empty and the pressures on the gauges stabilize again. Normal pressures are 35 to 45 psi on the low-pressure side and 300 to 400 psi on the high-pressure side. Add additional cans of refrigerant until the desired pressures are reached.

Items you will need

  • R-134A gauge set

  • R-134A refrigerant

 How to Charge the AC in a Dodge Caravan

Check your Caravan's air conditioning line for air conditioning leaks before attempting to add refrigerant. Auto parts stores sell leak-detection kits that you can use to detect leaks while also sealing small ones. Follow manufacturer's directions on how to use the leak detection kit you choose. If there is a large leak, do not add refrigerant; instead, take your Caravan to a professional.

Find the Low Pressure Side service port. It is marked Low and is black in color. Remove it.

Turn on the A/C to the coldest, highest settings possible. Use a pressure gauge to make sure there is pressure. If the pressure gauge is not measuring any pressure, then there may be a bigger problem that needs the attention of a professional.

Attach the hose to recharge the refrigerant on the Low Pressure Side. Open the valve so the refrigerant can flow into the system. Keep the can upright. When it is emptied, remove the refill hose and close the cap.

Turn on your air for 30 minutes to allow the refrigerant to make its way completely through the system. Check the pressure again; it should have increased. If it has not, add more refrigerant.

Items you will need

  • A refrigerant such as Freon-12

  • Charging tools

  • Leak detection kit

 How to Charge the A/C on a 1992 Buick

Park the vehicle on a flat, level surface and turn the engine off. Open the hood and locate the air conditioning plumbing along the passenger side of the engine bay.

Locate the low pressure charging port on the air conditioning line that goes from the accumulator to the compressor. Remove the cap covering the low pressure charging port.

Connect the recharge service hose and valve to the can of refrigerant. Turn the valve on the hose to puncture the top of the can. Slowly turn the valve in the opposite direction to fill the hose with a small amount of refrigerant. This will also expel trapped air from the service hose.

Close the valve and connect the hose to the low pressure charging port. Hold the can upright to prevent fluid inside of the can from entering the A/C system. Use a thermometer attached to the central A/C vent inside the vehicle to measure the A/C system's cooling performance.

Start the engine and turn the vehicle's A/C system to the "High" or "Max" setting. Open the valve on the service hose to allow refrigerant vapor to flow out of the can and into the A/C system. Depending on the size of the can, it may take up to 10 minutes to add the vapor inside the can into the A/C system.

Monitor the gauge on the service hose to prevent overcharging. If the reading on the low pressure charging port is between 25 to 40 psi with the A/C compressor on, the system is fully charged.

Close the valve on the can and disconnect the service hose from the low pressure charging port. If you need to add another can of refrigerant, remove the recharge service hose from the empty can and attach the hose to the new can of refrigerant. Repeat the procedure above for adding the additional can of refrigerant to the A/C system.

Items you will need

  • Recharge service hose and valve with gauge

  • R-134a refrigerant

  • Thermometer

 How to Charge the A/C on a Saab

Park your Saab on level ground. Ensure that the emergency brake is fully engaged. Place your Saab in neutral (manual trans) or park (automatic).

Locate the Saab's low-side pressure connection. It is capped and looks like a thicker relative of a tire valve stem. Also, it is normally featured on the metal pipe between the compressor and the drier. Take the cap off the low-side pressure connection and attach your refrigerant refilling kit.

Leave the kit in the engine for a moment. Be sure to position it far away from engine parts that will shift or otherwise move.

Open all the doors of the Saab or, if you prefer leaving the doors closed, roll all the windows down.

Run the engine and let it fully heat up. Turn on the air conditioner. Put the air on the coldest setting, with the blower on high.

Return to the Saab's engine compartment. Place a thermometer in the Saab's internal, central air conditioning duct.

Turn down the nozzle atop the refrigerant container. The nozzle will pierce the refrigerant container's seal, and refrigerant will charge into the Saab's air conditioner. Let the charge last for one minute, then shut off the charge.

Let the system rest for one minute. The air conditioner's blower will circulate the freshly added refrigerant. Keep an eye on the system's pressure by monitoring the gauge on the refrigerant's refilling kit. Continue adding refrigerant at one-minute intervals.

Monitor the temperature within the Saab's air conditioning system. As more refrigerant is added, the internal temperature will slowly drop. When an air conditioner is set to its coldest level, it refrigerates air to 40 degrees. When your Saab reaches this temperature, the system is charged. Also, you will notice the air conditioner's metal pipes will be evenly cold all over. However, on a hot day, the system may level out before 40 degrees. This is acceptable, as the system will level between 40 and 60 degrees on hot days.

Shut off the flow of refrigerant. Detach the refrigerant's refilling kit from the low-side connection. Run the air conditioner for 10 more minutes. This ensures that the refrigerant has circulated fully through all of the Saab's air conditioning components.

Items you will need

  • Refrigerant refilling kit

  • Thermometer

 How to Charge the A/C on a 1998 Honda Accord

Place the recharge hose onto the bottle of the R134a refrigerant. Keep the valve closed until you are ready to charge the air conditioner.

Locate the low-side quick-connect valve on the hose that connects the accumulator and the compressor -- it is located on the passenger side of the Accord, and it has a black cap. The quick-connect coupler on the recharge hose only connects to that valve.

Remove the cap from the quick-connect valve on the hose and snap the recharge hose onto the valve.

Turn on the air conditioner on "Full" on the Honda Accord and open the valve on the recharge hose.

Turn the valve off when the pressure gauge reaches 35psi. If you surpass 50psi, the system will be over-charged.

Turn off the air conditioner, close the valve on the recharge hose and disconnect the hose from the low-side valve. Place the cap back onto the valve.

Items you will need

  • R134a recharge kit