Causes And Solutions For Car A/C Pressure When Off

If you find that the car A/C pressure in your vehicle is lower or higher than normal, even when the engine has been deactivated, it means that you have a problem. But knowing how to assess the A/C pressure is essential so you can avoid false readings.

The Condenser Has Malfunctioned

The condenser plays an important role in the absorption of higher temperature and pressure from the compressor. It is designed in such a way that it is supposed to alleviate heat while lowering Freon and refrigerant temperatures.  If the condenser is damaged or becomes faulty, this means that it won’t be able to manage the pressure which is created by the A/C, which will lead to a higher pressure environment even in cases where the engine has been shut off. However, to figure out what is causing the issue, you’ll need to test the cooling system while its engine is activated. It is possible that air might have gained entry within the coolant system, which is what causes the pressure.

The A/C Is Overcharged

Air conditioning systems are subject to becoming overcharged, which can result from excessive refrigerant or too much oil. Both will cause an abnormal pressure buildup that needs to be released, and it is best to hire a mechanic to do it on your behalf.

The Condenser Fan Is Faulty

Condensers use fan motors, and if there is a buildup of debris, dirt, or grime within the system, airflow can become blocked which will damage the fan. Additionally, the system will be unable to cool itself down. In such an environment, the fans will be subject to extremely high pressure which can degrade the aluminum, culminating in evaporator coil leakage. If not addressed in time this could lead to the destruction of the entire air conditioning system.

What You Should Do About Abnormal AC Pressure

You’ll want to start by performing a general inspection of your vehicle’s air conditioning unit. If you don’t have the time, knowledge, or inclination to do it yourself, you can hire a technician who will help. If debris is found within the system, it will need to be thoroughly flushed out. Getting the oil or dirt out might require you to disconnect your compressor, expansion valve, or drier.

If you haven’t already done so, you might want to consider retrofitting the system from the R-12, since mixing oils or refrigerants can lead to system damage. If upon reaching your expansion valve you find that it is also dirty, you’ll want to wash it gently which can be done with water but be sure not to get liquid on the pipes that may come into contact with the freon. If the expansion valve appears damaged you might want to replace it.

Finally, you will want to flush out the system, which will require spraying the flushing compound inside the pipes. You’ll want to wait for around twenty minutes then flush out the compound with shop air, and if the compressor is leaking you’ll want to replace it.