How To Recharge Car Air Conditioner: (With Pressure Chart)

How To Recharge Car AC

If the air in the cabin is not cool as it used to be while the AC is ON, then there is a maximum chance that refrigerant escaped from the system. A reduction in refrigerant will not let the AC perform at full capacity. To bring the AC system back to its maximum efficiency, AC needs to be recharged.

In this powerful guide, you are going to learn the car AC recharge in four minutes with six quick & easy steps including the pressure chart.

Related Post: How To Fix Car AC Compressor Clutch Not Engaging

How To Recharge Car Air Conditioner

Step-By-Step Procedure

This guide consists of recharging the car AC system with refrigerant r-134a. Below is the step-by-step guide to quickly recharge the car AC with six steps.

Step 1. Inspect The Entire System

Inspecting The AC System
Inspecting The AC System
  • Before recharging the AC system, inspect all the AC components. Inspect for leaks, damaged pipes, and loose bolts.
  • Make sure the compressor is working perfectly.
  • Look for AC components that they do not touch so that they do not rub and eat away from each other.

This is an Info
Recharging the car AC is a temporary fix, you should fix the underlying problem before recharging.

This is an Info
If the AC compressor’s clutch engages, it means the AC system is low on refrigerant, provided that the AC is blowing slightly cold air. If the AC compressor’s clutch does not engage, it means the AC system has too low refrigerant or the compressor has failed or there is an electrical issue.

Related Post: Parts of Car AC System

Step 2. Be Save

Safety Glasses And Gloves
Safety Glasses And Gloves

Always wear safety glasses as refrigerant is unsafe for the eyes. Also, wear gloves and read all instructions written on your recharge kit.

Step 3. Locate The Low-Pressure Port

Car AC Low Pressure Port
Car AC Low-Pressure Port

Before finding the low-pressure port, you need to know the background of the pressure pipes. There are two types of pressure lines, high and low-pressure lines. Remember, never use a high-pressure port for filling the refrigerant in the car AC system.

Recognize the low-pressure pipe, which is larger in diameter compared to the high-pressure pipe. The low-pressure pipe comes out of the firewall (The metal wall behind the engine) to the compressor. Trace it. It has a cap cover labeled “L”. Remove it and clean it

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Step 4. Connect The Charging Hose

AC Recharging With Low Pressure Port
AC Recharging With Low-Pressure Port

Connect and tighten the charging hose to the low-pressure port.

Step 5. Run The Engine

Beautiful Girl Starting The Car
Beautiful Girl Starting The Car

Start the engine and press the AC button. Does the compressor clutch engage? If not, it might be an indicator of low refrigerant.

If the pressure is below 20 psi, then the compressor will not engage.

Step 6. Add Refrigerant

Adding Refrigerant In Car AC
Adding Refrigerant In Car AC

Now connect the refrigerant tank rubber hose to the low-pressure port. Continue to dispense the refrigerant for 5-10 seconds, then wait 30 seconds for the pressure to equalize. Also, keep an open eye on the pressure gauge to monitor the pressure until you get the desired level.

Almost 40 psi is enough for the greatest cooling. You can also take help from the below pressure chart. You have successfully recharged your car AC, now it should be colder.

This is an Info
Be careful not to overfill the car AC with refrigerant. It can cause damage to the air conditioning system.

This is an Info
Still, If you are not sure about how much refrigerant should be added. For this purpose, put a thermometer into the AC vent near the steering wheel, Turn On the AC and note the temperature of almost 28 degrees Celsius is the fully charged temperature.

Automotive AC Recharge Pressure Chart: R134a

Car AC Pressure-Chart
Car AC Pressure-Chart


Remember:- The process of charging and recharging is the same. The difference between charging and recharging is. In charging the system, AC parts are retrofitted, the system is evacuated for 30 to 45 minutes and a proper amount of lubricating oil is added. Then the other procedure is the same, which is mentioned above.

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Do You Charge AC On The High Or Low Side

Always use a low-pressure port for recharging. It is because the low side of the AC system has less pressure and the refrigerant can easily enter the car AC system. This will help to avoid any potential damage to your unit and will also help to maintain its efficiency.

Frequently Asked Questions (FAQs)

Can you recharge your car AC yourself?

The answer to this question is somewhat complex. In short, it depends on the make and model of your car, as well as your own personal level of experience and expertise. Some car AC systems are relatively simple and can be easily recharged by the average person, while others are much more complex and should only be handled by a trained professional.

Does the car need to be running to recharge AC?

The car’s engine must be running in order for the AC to recharge. First, it is important to understand that the car’s AC system is powered by the engine. The AC compressor is driven by a belt that is connected to the engine. When the engine is running, the AC compressor will turn and circulate the refrigerant in the system. This process helps to cool the air that is sent into the car. However, if the engine is not running, the AC compressor will not turn and the system will not be able to recharge.

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