No matter what car you have, no matter how advanced the features are, you can easily face issues with your car’s AC. Among various problems, the most common one you may face is AC pressure too high. This is a problem many car owners have to go through, in general.
So, if you are having such kind of trouble then, this is the article for you. Here, I will go through a complete overview of why this happens and how to solve it. Without wasting further time, let’s get going with it.
What do your car AC pressures mean? AC pressure readings telling about my AC pressure
Now, how would you know if the AC pressure of your car is too high or maybe too low? What’s the perfect number to have for your AC pressure? Before I go ahead and answer those, I would like to begin with the meaning of AC pressure numbers.
Usually, there is a gas called refrigerant in an AC, which is responsible for all the temperature control. It changes its state in different pressure ranges. With the proper pressure PSI, it will act adequately and keep your car cold through the AC. So, the AC pressure on your car means it has the right PSI to properly process the refrigerant.
Typically, you don’t need to worry too much about low pressure as they don’t impact the performance. What you should be looking at is the PSI of high pressure. The best PSI to have as your higher pressure is 150 PSI.
However, you may get different readings on your car AC. So, let’s take a look at what those different readings mean for your AC.
- 250 PSI high / 30 PSI low: This pressure usually indicates that there is air inside your system somewhere.
- 250 PSI high / 50 PSI low: With this reading, you can assume that your condenser is blocked and it’s not cooling.
- 225 PSI high / 80 PSI low: This kind of pressure reading usually comes when too much refrigerant is inside the system.
- 200 PSI high / 70 PSI low: When you see this reading, it signifies some blockage in the system.
- 160 PSI high / 10 PSU low: This indicates a problem with the piping, evaporator, or expansion valve.
- 150 PSI high / 30 PSI low: It tells you that there is water in your system.
- 150 PSI high / 10 PSI low: This pressure is a clear sign of leaking in the system.
- 125 PSI high / 30 PSI low: It’s the pressure you get for insufficient charge in the system or having excessive oil in your compressor. ‘
- 100 PSI high / 100 PSI low: No power coming to the compressor or having a burnt coil brings this pressure reading.
- 50 PSI high / 50 PSI low: Issues with clutch engagement
Usually, whenever you see these readings on your AC pressure, you should have these particular problems. So, when you know the problems, you will be able to fix them quickly. That’s why knowing what the readings mean can be very crucial for you.
Related: air in heater core
Why is car AC pressure too high?
There is no single reason for your AC pressure to be too high. It goes high due to several reasons. Here, I will go through all the reasons causing high pressure on your car AC.
Malfunctioning condenser fan
This is one of the most crucial reasons for having high pressure on your car AC. When the condenser fan isn’t working properly, it fails to liquify the coolant because the function of a condenser fan is to keep the coolant cool that eventually leads to keeping the AC pressure proper.
So, whenever you face this issue, the best solution is to replace or fix the condenser fan. You will have to opt for replacing most of the time because it’s tough and sometimes impossible to fix the fan.
An overcharged system
Now, this is another common reason for this problem to happen in your car AC. How does a system get overcharged? Well, when there is too much refrigerant inside your system, you can call it an overcharged system. The first thing you have to do here is to stop adding refrigerant since the problem is having too much of it anyways.
The pressure you get from the proper coolant amount in the system is indicated on the refrigerant you use. For example, the R134A refrigerant should have 130 to 150 PSI which is the standard pressure for this refrigerant. You can check up yours in the package.
AC coils contamination or leakage.
This is a problem that requires your immediate attention. What happens here is that your piping system gets leaked and then contaminated. This can also cause by wrong refrigerant oil usage. Any kind of leakage is a grave cause for contamination in the coil or piping.
Because of the contamination, the coolant doesn’t perform the way it’s supposed to. This leads to your AC pressure getting high.
Mostly these are the reasons that can lead to higher pressure in your car AC. If you checked up on these and see no signs of these causes, you might seek professional help.
Related: How to bypass the AC pressure switch
How to lower the pressure in car AC?
There are several ways to lower the pressure in your car AC. You can either solve the issues I talked about above or try out a different method. First, let’s check out the solutions to the above problems.
- When you have a malfunctioning condenser fan, there are two ways to go about it. You can fix the fan, which can be very tough and sometimes impossible. Or you can replace the fan, which is much easier to do. All you have to do is get a replacement fan and replace it. It doesn’t take too much effort to fix condenser fan problems.
- There are some things you have to do for the contamination issue or leakage issue step by step. The first thing to do is get rid of any contamination through vacuuming. You have to vacuum your system, so it doesn’t get contaminated further. Then, clean up the contaminants and seal the leakages.
Keep in mind that this is a fix that isn’t permanent. In such cases, it’s better if you can replace the affected parts.
Related: What Does a Blend Door Actuator Do
These are the quick fixes you can try out and see if the pressure in your car AC goes lower or not. If it doesn’t, then you can follow the method I am going to discuss now. This method works when you are dealing with an overcharged system. Here’s what you will be doing.
- First of all, you will need to get the hose you use to fill in the refrigerant. You have to use this to take out pressure from the coolant.
- Keep in mind that you have to hook it up and close the vent entirely. You should see a pointy part from the hose. This ensures that nothing will come out when you hook up the hose.
- Now, use the hose and put it in the same spot where you usually fill the refrigerant. This will allow you to take out air slowly out of the AC. You can reduce the pressure with the extraction of air with ease.
- To check if it’s working or not, you can touch the pipe. If the pipe is cold and sweating a bit, then this is working. Otherwise, it’s not. You may need to use a different hose. You can also use a pressure gauge to test the pressure.
- This may not work in the first go, so test it out by turning your AC on. If it doesn’t work, you should do it one more time and let some pressure out.
There are some things you will need to be aware of when you attempt this method. It would help if you had safety gears on you. You have to wear gloves and glasses because the air that comes out of pressure is usually very cold. If you are not careful, it can burn your hand and damage your eyes as well.
Also, if you have a hose with a trigger, the process gets much more accessible. You can use the hose with one hand and have more control over the air coming out.
Related: air conditioner problems
All in all, you don’t want your AC pressure too high for a long time. It can have permanent damage to your system, which will cost a lot to repair. Now, depending on your AC going through high pressure, you can go with the specific solutions.
Before attempting the method I shared here, you must make sure that you face an overcharged system issue. This method doesn’t work if you have issues like condenser fan failure or leakage and contaminant problems.
James is a certified auto technician specializing in commercial vehicles. With 30 years of experience under his belt, James has encountered almost every type of automotive issue there is! Besides his day job at the repair shop, he is also an amateur race car driver.