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Does Evacuating Car AC Remove Oil?

Evacuating the AC system from a car is crucial. For extended journeys, it guarantees that the AC is in excellent condition.  In this post, we have carefully researched the question for more details regarding the evacuation of your Car AC and its implications on other components like oil.

For an AC refrigerant evacuation, only the air and humidity are removed, not oil. To remove oil from a car's AC system, the system can be removed and its components cleaned with a special solvent.

The air conditioner of a car plays a vital role in the comfort and pleasure that comes with driving a car. However, its maintenance is important too. Hang on and keep reading to learn how to properly evacuate your car AC and the role of oil in the system. 

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Disassembly of an old and worn car radiator by a mechanic, Does Evacuating Car AC Remove Oil?

What Does Evacuating Car AC Mean?

The removal of moisture, air, and non-condensable gases from a refrigeration system is known as refrigerant evacuation. The sealed HVAC system is put into a vacuum during this procedure using a vacuum pump. This purges the device of nitrogen, moisture, and air.

All traces of air, moisture, and nitrogen are eliminated from the system by vacuuming them. Non-condensable gases like air and nitrogen can result in high head pressures, high discharge temperatures, ineffective operation, high-pressure tripping, and system failure.

Compressor failure may result from component blockage caused by moisture and potential acid production. Only oil and refrigerant should be present in a system that has been properly charged.

A modern diesel engine with 170 horsepower and an engine capacity of 2.2 liters

Does Evacuating a Car AC Remove Oil?

While the process of evacuation eliminates moisture, it does not clear the air conditioning system of oil or debris. For the same reason, sludge and deep vacuum methods cannot replace liquid-line or suction line driers. Only proper filtration can remove particulates and sludge. 

The procedure that removes all traces of air and moisture from the system is referred to as evacuation. In order to evaporate the moisture, the vacuum pump lowers the system pressure.

Engine concept of an ac air filter

The vapor, together with any remaining air, is then evacuated. The pump's capacity to remove all the contaminated moisture by boiling it off is directly correlated to its ability to drop the pressure and create a vacuum.

How to Evacuate Car AC

Evacuating the AC involves employing the right tools, including a vacuum pump, AC recovery unit, and manifold gauges, and it necessitates strict attention to the OEM's suggested procedures. The entire operation takes between 30 and 60 minutes.

The following are steps in evacuating your AC:

Purchase the Right Equipment

Before attempting to repair the air conditioning or AC system in your car, put on safety goggles and gloves. Additionally, ensure the following are prepared:

  1. Manifold gauges serve as the vehicle's system's focal point.
  2. All of the air in the recovery tank should be removed by the vacuum pump.
  3. All of the refrigerants should be moved to the recovery tank by the AC recovery unit or machine.

Get the Recovery Tank Ready

By releasing the nitrogen in the tank and opening the valves, you can prepare the recovery tank. Establish the vacuum pump. By connecting a vacuum pump to the blue valve on the recovery tank, air and moisture can be extracted from there.

Rentals are available through car dealerships. As you do this, make sure your recovery tank valves are shut. Then start the vacuum pump and open the blue valve at the same time. To completely purge the recovery tank of air and moisture, turn on the vacuum pump and let it run for about an hour.

Clean out the Recovery Tank

Close the vacuum pump and the recovery tank valve. Make careful to complete the initial stages in this precise order. If you don't want to generate a vacuum, you can suck the oil from the vacuum pump into the recovery tank.

Get the Manifold Gauges Ready

Connect the gauges on the manifold. Before attaching them to your car, double-check that they are shut. Take note of the high and low-pressure sides under the hood of your car as you do this. Between the condenser and the expansion valve/orifice tube lies the high-pressure port.

The return line between the compressor and the evaporator/firewall has a low-pressure port. Connect the red manifold connector to the high-pressure side and the blue manifold connector to the low-pressure side.

Don't worry about size compatibility because these connections' end fittings vary from one another and are color-coded.

Connect Hoses to the recovery unit

Connect the "in" connection on the AC recovery unit or device to the corresponding port on the yellow manifold connector.

Next, take another yellow connection and attach one end to the "out" port on the recovery unit and the other end to the blue valve on the recovery tank.

Remove Air and Moisture from the AC System

Opening the blue valve on the recovery tank gradually while keeping a watch out for leaks. Then, to drain liquid from the AC system, open the blue liquid valve on the manifold gauges. Open the red vapor valve on the manifold gauges when you're finished.

The system of the car should now be completely evacuated. Wait until the manifold gauges reach zero, which should take 30-45 minutes, before stopping the evacuation operation. A readout below zero indicates that the system can maintain a vacuum, which is better (proof there are no leaks in the AC system).

To Note

After shutting off the vacuum pump and pressure lines, keep the manifold gauges connected to the car for at least 30 to 60 minutes. You are assured of an AC system free of leaks if the readout remains the same.

The optimum full vacuum is 29.6 inches of mercury, however, most vacuum pumps only manage 20 to 25 inches. Vacuuming periods may therefore take longer than those specified in this guide to achieve the necessary effects depending on the type of vacuum pump used to evacuate the AC system. 

Manifold Gauge Connectors Must be Disconnected

Close the red liquid and blue vapor valves when the manifold gauges show zero. On the recovery unit, however, close the inlet valve/port before the outlet valve/port. Next, completely shut off the recovery device.

Close Any Other Open Valves

Before removing the lines or connectors, close the blue valve on the recovery tank. In the same sequence that they were connected, unplug the wires and connectors. Start by unplugging the lines inside the vehicle. Next, unplug the lines connected to the recovery unit, and last, unplug the yellow line that runs from the AC recovery unit to the recovery tank.

Changing the Service Port Covers

Last but not least, swap off the black dust caps that were previously on top of the low and high-pressure lines under the hood of your car.

Do I Need to Add PAG Oil After Vacuum?

If an air conditioner has been evacuated, you might be asking if the oil has to be added. In many situations, you do, but there are a few things to keep in mind. First off, if the refrigerant is empty, you shouldn't add oil.

Nitrogen, oxygen, and water vapor are all components of the air in the system. Degassing or evacuating is the process of removing this air and water vapor.

An oil-logged air conditioner may have a malfunctioning condenser fan motor or dirt around the fan as the culprit. The oil will not be removed from the system by evaporating the air conditioner, but it will remove the air and moisture.

No more than four ounces of oil should be present in the system. Nevertheless, depending on the capability of your car's AC system, you should add oil in the right quantity. To avoid poor cooling and early compressor failure, you must be careful not to overload the system with oil.

The effectiveness of your air conditioning system depends on how much oil is used in it. In accordance with the owner's handbook, regularly check the system's oil level.

Low oil levels have a serious negative impact on the entire system. Checking the oil level frequently is always preferable to taking the chance of damaging your air conditioning system.

How Long Should You Evacuate a Car AC System?

Young mechanic recharging car air-condition in auto repair shop

The AC system should be evacuated once a system has been opened for any repair, servicing, or installation, even for a little period of time. The easiest technique to eliminate non-condensable gases (NCG) from a system is to draw a strong vacuum inside it.

Low and high air conditioning system sides draw a strong vacuum for at least 5 to 45 minutes when a vacuum pump is attached to both.

For the removal of any moisture that may have entered the system along with the non-condensable gases while it was open, a vacuum of approximately 500 microns or 29.92 hg gauge pressure is required.

The replacement of the AC receiver/drier or accumulator should be done in tandem with performing a deep vacuum because this will help to reduce moisture inside the system.

Do AC Compressors Come With Oil in Them?

compressor, Vehicle Part, Engine, Machine Part, Commercial Land Vehicle

In many cases, AC compressors are pre-filled with enough oil to power the complete AC system. New AC compressors typically arrive packed with oil.

They naturally contain the proper kind and quantity of oil to keep the air conditioner running for an extended period of time. However, before installing the AC compressor, make sure it has enough pre-filled oil to prevent any damage.

In Conclusion

Disassembly of an old and worn car radiator by a mechanic

It is important to note clearly that when evacuating your car AC, oil is not lost as what is been removed is moisture. We are hopeful that the details provided are useful and helpful to your question and can help you handle issues that relate to your car AC.

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Car AC Leaking Water - What Could Be Wrong?

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