How to Vacuum Car AC System Without Pump

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Written By Nicklaus Frost

Last Updated on: 28th June 2022, 02:28 pm

If you don’t vacuum out an AC system, you won’t be much benefited from that AC performance. A minor amount of air, humidity, moisture, or water stays there and ignites the new refrigerant inside the AC system. A clean vacuuming will keep the AC system at ambient temperatures.

People ask, Is it necessary to pull a vacuum on the AC system? Yes, it is essential to do that. By vacuuming the AC system, you can remove air or moisture from the air-conditioning system. It seems to be a severe problem. The humidity is known to be a serious problem to reduce AC’s performance. On the other hand, the water causes the AC system to freeze. Also, the air causes high condensing pressure on the side of the refrigeration system.

How to vacuum a car AC system without a pump? Before detailing this answer, we would recommend tracking the vacuum pressure and setting the vacuum pumps to 29 inches of mercury (Hg) if possible. Vacuuming for half an hour inside the AC system will get you rid of moisture and dust inside the automotive AC system.

If you don’t want to use a vacuum pump, you’ll have to install an access valve on the low and high sides of the AC system. This will help you learn how to vacuum car AC system without pump.


How to vacuum car ac system without pump; 5 steps


The steps for vacuuming an AC system without a pump are as follows:

  • Depress the access valves on the AC system
  • Charge the low side valve
  • Turn the high side valve pressure off
  • Again, charge the low side and turn the high side valve off
  • Finally, fill the AC system with refrigerant


  • Depress the access valves on the AC system

Firstly, it’ll be necessary to install access valves on the compressor’s high and low sides. The following work is to depress the high side access valve and specify the low-side compressor pressure. The pressure will reach close to the high side valve and shut off the compressor.

  • Charge the low side valve

Have you seen the result of step one? Now, it’ll be necessary to fix the low side of the AC system with 14 psi. Running the pressure for a few minutes will equalize the high and low side pressure successfully.

  • Turn the high side valve pressure off

Hopefully, you pressured the high and low side valve successfully. Make sure both of the access valve pressures are leveled out. Now, you should turn the compressor behind the access valve and depress it on the high side valve efficiently. Once you run the pressure on the low side, please allow the high access valve and the compressor to close.

  • Again, charge the low side and turn the high side valve off

Now, you’ll have to repeat setting the downside of the system in 14 psi for three minutes and equalize the pressure. Then, it’ll be required to turn back the compressor ‘ON’ & depress the high-side valve. You’ll undoubtedly see a successful difference, like the system’s low side is not reaching as low as the previous version. During the process, if you get any gas, air, or moisture that is not coming out of the high access valve, please shut the valve. The vacuum process is almost done for the AC system without a pump.

  • Finally, fill the AC system with refrigerant

The last step suggests charging the AC system with the refrigerant. Your instruction guide or owner’s manual proclaims the right amount of refrigerant. After implementing the refrigerant to the AC system, please shut down the compressor. You may need to make a bit more adjustments based on your specific unit.

Things you may need:

WORKSHOP Wet/Dry Vacuum Accessories

Automotive Car Air Conditioning Flushing Gun Combo

FJC 6014 Vacuum Pump Adapter

Vacuum Down and Recharge an Air Conditioner

It is often an honest question, How to vacuum the AC system in your car? Well, you’ve got two options, like cleaning the system with a vacuum pump or adding some refrigerant to the AC system and then recharge it. It would help if you did not take the vacuum option for granted but routinely clean out the unit’s dust and moisture. Whenever you take your vehicle for a service, we recommend being mindful of having the AC system vacuumed.How to Vacuum Down and Recharge an Air Conditioner

Please read our simple steps to recharge the AC system with refrigerant-

  1. You should maintain precautions first before all starting the procedure. The first tip is to take your car or vehicle to a safe place. You’ll have to turn the engine off, turn the emergency brake ‘ON’ & park the tires on an incline. Working with gloves will be great!
  1. The next thing! Please purchase a simple recharge kit on Amazon; offers are going on there! Once after having the refrigerant kit in hand, you’ll have to identify the low side system service port. It is found on the two refrigerant lines mostly.
  1. Hopefully, you’ve found the low-side service port. Now, please remove the dust cap from there. On the other hand, you’ll have to make up the service port. Attach the recharge kit to the state!
  1. Have you attached the recharged kit successfully? You get a proper state of charge through the gauge. Please wait till the low side system is fully charged.
  1. With the refrigeration kit attached to the low side pressure, turn the engine ‘ON’ and fix the highest setting’s AC system. After 30 seconds, the compressor will create proper operation and drop the excessive pressure
  1. Now, it’s time to release the refrigerant. You need to press the plunger valve to release the refrigerant. Releasing the refrigerant for a few minutes will give the correct pressure. Don’t overfill the system.
  2. Then, turn the ignition off. It will turn both the engine and the AC off. Please release the unit off to the service port and reinstall the dust cap on the service port.


We have tried discussing how to vacuum a car AC system without a pump even though using a vacuum pump and then evacuating your AC system is the most common and beneficial method. Vacuuming the air-conditioning system is vital to discharge excessive air or moisture from the AC system and saves your system from damage. Why don’t you conserve efficiency in an expert’s ways? Thanks, us later!

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