How To Add Freon To Car: 6-Step Guide And Troubleshooting

How To Add Freon To Car: 6-Step Guide And Troubleshooting

May 24, 2021 0 By onroadtips

One hot summer day, you get into the car, turn on the engine and the air conditioner. However, a few minutes later, you notice that the air is not as cool as it’s supposed to be. When this happens, it’s likely that the refrigerant in the AC system is running out, which takes a short time to refill. With that in mind, Onroadtips has compiled a comprehensive guide on how to add Freon to car.

Freon is a trademark of several halocarbon products made by The Chemours Company. They are non-flammable, low-toxicity, and stable gases or liquids commonly used as refrigerants.

Before starting with the guide, it’s worth noting that it applies to 134a and r-134a refrigerants.

How To Add Freon To Car: Applied to r-134a refrigerants
How To Add Freon To Car: Applied to r-134a refrigerants

How does an air conditioner work?

An A/C comprises of three major parts: an evaporator, a compressor, and a condenser. The evaporator and condenser are connected in a loop while the compressor is placed between them.

The system is filled with r-134a fluid, which is compressed by the compressor then sent to the condenser where the heat is released to the outside. After that, the liquid refrigerant goes to the evaporator inside the passenger compartment and expands. Here, it removes heat and cools down the evaporator. Then, the fan directs the air over the evaporator and through the air vents into the car.

How does a car A/C work?
How does a car A/C work?

How to add Freon to car?

Step 1: Prepare

First of all, if your car was made before 1994, it likely requires R-12, meaning this post is not for you unless the vehicle has been converted to be compatible with r-134a.

You need to prepare:

  • 0.7 liters of r-134a refrigerant
  • A refrigerant dispenser
  • A pair of goggles

Step 2: Assemble the dispenser

This is when you should put on the goggles. After that, insert a can of refrigerant into the dispenser’s bottom and screw it in.

Put on the googles when you assemble the pispenser
Put on the googles when you assemble the pispenser

Step 3: Make sure the compressor is running

The first thing to do in this step is starting the engine. Next, you need to turn on the A/C while the fan must be turned to maximum. Then, follow the hose that runs from the low side fill port to the compressor, which is attached to the engine.

After that, find the pulley on the compressor. If the center part of the pulley is spinning, it’s good and engaged. Otherwise, you need to add half a can of r-134a and see if the compressor is engaged. If it’s not, your car needs to be taken to a mechanic.

You are supposed to let the engine run and the A/C at maximum until you have finished refilling.

Step 4: Locate the refrigerant fill port on the low-pressure side

Open the hood and look at the low pressure side of the system to find the refrigerant fill port, which will have a small plastic lid featuring an “L” on the top. Once you’ve found it, unscrew the lid.

If you have trouble finding the fill port, here’s a brief guide for you: in most cases, you can find it on the engine bay’s left side. The fill port is usually a small section of metal pipe with two lengths of rubber hose that come off its ends. The back of the engine bay is the firewall. There should be two pipes sticking out from the firewall, one of which is larger than the other.  By following the larger hose, you will be able to locate the low pressure side fill port.

Remember not to touch anything that you are not familiar with because almost everything under the hood either moves or gets hot, especially the high pressure side.

Step 5: Attach the dispenser

Firstly, grip the connector on the end of the hose then lift its outer sleeve. Now, you need to squeeze the trigger for 2 seconds in order to remove air from the hose.

As you are squeezing and lifting the sleeve, also press the connector onto the fill port. Then, release the connector’s outer sleeve and the connector, which should then snap into place on the port. Next, let go of the trigger. Lastly, pull the connector gently to make sure it’s seated on the fill port properly.

Step 6: Recharge

You need to find out what pressure to fill to, which can be found in the table coming with the dispenser you’re using that shows the lowest and highest acceptable pressures for the current environment temperature. Some gauges feature an adjustable ‘V’ to highlight the proper pressure range.

If the dispenser’s needle reads below the minimum acceptable level of pressure, you can start recharging the system. Follow this instruction of how to add Freon to car with gauges:

  1. Squeeze the trigger for 5 to 19 seconds while tipping and shaking the can slowly. But do not turn it upside down.
  2. Wait for 30 seconds while the pressure equalizes.
  3. Read the pressure shown on the gauge, if it’s too low, keep filling the refrigerant. Keep in mind that you should measure the pressure only when the compressor is engaged.
  4. Once you’ve got the right pressure, stop recharging the system then wait for a few minutes.
  5. Check the pressure again then remove the dispenser hose and place the protective cover on the fill port.

Once the last step is done, the A/C should release cold air. So, here’s the step-by-step guide on how to add refrigerant to car AC.

How to add Freon to car ac: What can go wrong?

The needle is not moving

If you think the needle is not moving or the refrigerant is not going into the system, be patient. The reason is that for the pressure to rise, it requires a certain amount of refrigerant.  

If you have waited for a while and the pressure still does not rise, you should check if the dispenser is properly connected to the fill port.

Too much refrigerant is added

If you think you have accidentally added too much refrigerant, check to see whether the condenser has disengaged because when this happens, the pressure can reach a high level.

The compressor does not engage

When the compressor does not engage, you can try adding half a can of refrigerant. If it still doesn’t turn, the compressor may be broken. In this case, you must not add any more refrigerant and should take your car to a mechanic.

All in all, we hope that this post has helped you figure out how to add Freon to car and will be able to do it properly. It’s also worth noting that you are not allowed to release any refrigerant into the atmosphere, so, be careful.