AC Low-side pressure too high: causes and how to fix 

What can cause the AC low-side pressure to get too high? Auto air conditioning systems commonly experience high-pressure buildup on the low side. However, it’s a circumstance you want to avoid, especially in the hot summer. When the AC pressure is too high, the temperature rises to a point where it is uncomfortable on a sunny day. The unit is slowly being damaged, and the situation indicates that there is a big problem.

AC Low-side pressure switch too high

When AC low-side pressure rises too high, the system will be unable to produce the necessary temperature to cool the car. Today, I will be discussing what it means when low-side pressure is too high. You’ll get to know the causes, the testing, and how to fix the AC low-side pressure too high issue.

Read more: Understanding AC pressure switch


What does it mean when AC low-side pressure is too high?

When AC low-side pressure is too high, the system is unable to produce the necessary temperature to cool the car. There are various possibilities that could apply to this situation. There may be a leak in the system or an issue with the compressor or refrigerant that was added to charge the air conditioner.

The low side of an AC system is the line connected from the compressor to the evaporator. On most vehicles, it has a colored cap, blue or black, that must be removed when recharging the AC system. The low-side tube or line usually has a larger diameter than the high-side tube.

What causes the AC low-side pressure to get too high?

Here are some of the things that can cause the AC low-side pressure to get too high:

  • A failing AC compressor
  • Overcharged AC
  • Damaged condenser fan
  • Testing the AC pressure

A failing AC compressor

It is often the compressor’s fault if the low-side pressure is too high and the high-side pressure is low. Even when the AC system is turned on, you won’t get cold air because the refrigerant can never circulate without the compressor. This typically occurs if your AC system is not used for an extended period of time.

Read more: Understanding an Air Conditioning System

Overcharged AC

The system might simply be overcharged. Even when the engine is off, you will notice high pressure. This might be that there is too much oil present or that there is too much refrigerant in the air conditioning system. In either case, you have to relieve some of the pressure. This is something that should be done by a mechanic.

Read more: List of best quietest window air conditioner

Damaged condenser fan

Airflow through the condenser is reduced when the fan is damaged. It’s also possible that some of the airflows are being obstructed by debris, which would result in the same issue. A leak could develop as a result of the fan problems, which could lead to warm air blowing out.

A damaged fan will undoubtedly result from the low-pressure side’s inability to withstand these greater pressures, possibly even to the point of causing an evaporator coil leak. If this occurs, the air conditioning system will be seriously damaged and will need additional repairs.

Read more: Understanding AC condenser fan

Testing the AC pressure

If you have a good set of gauges, testing the AC pressure is easy to do. You should be aware of the recommended pressures for your vehicle, which may be found in the service manual. The car’s specifications can be found online if you don’t have the service manual close at hand.

Attach the pressure gauges for the AC. The AC system has two caps that you can see. one for the side with low pressure and the other for the side with high pressure. When compared to the other side, the diameter of the high-pressure side is smaller.

Your gauge will use a color-coding system to help you see the various sides. Blue is used for low pressure, and red is utilized for high pressure. Once the gauges are linked, start the engine of your car. Give it a few minutes to run so that the refrigerant can flow and you can get an accurate reading.

Analyze the reading and inspect the gauges. The low-pressure blue gauge should read between 25 and 30 PSI if everything is operating appropriately. On the other hand, a typical high-pressure setting is often between 200 and 250 PSI.

Remember that these summaries are merely estimations. The service manual for your vehicle may have different requirements. There is an issue if the pressure on one side is excessively low or high. To prevent more harm, you should have the system examined as soon as possible.

Read more: 4 signs that your car’s air conditioner needs freon

How to fix the AC low side pressure too high issue

There are a lot of things that can cause the AC’s low-side pressure to get too high. One of the causes of an AC low-side pressure that is too high can be a damaged or leaking evaporator coil. Replacing the damaged or leaking evaporator coil can resolve the issue. However, depending on the model of the car and the mechanic’s hourly rates, an evaporator replacement might cost anywhere from $850 to $1100 for parts and labor.

An overcharged AC system can cause the low-side pressure to get too hot. A mechanic would normally utilize a device that uses vacuums to discharge or bleed excess refrigerant from the AC to fix an overcharged AC system. The device will monitor pressure levels while it operates, and if they return to normal ranges, your mechanic will be able to determine that the AC system once again has an adequate amount of refrigerant. The extra coolant is kept in the machine so it can be utilized again later.

Having too much refrigerant in your car’s air conditioning system can lead to excessive heat and pressure, which may be the cause of your AC system blowing hot air out of your vent. An overcharged air conditioning system in your vehicle can damage the compressor if it fix.

However, we discussed that the issue can also be the result of a damaged condenser fan. So an AC condenser fan replacement typically costs between $300 and $425. Labor costs can range from $55 to $200, depending on your make and model, while parts might cost between $245 and $330.

Read more: Lists of Best Portable Air Compressors


What happens if the car’s AC pressure is too high?

The energy in the AC compressor may cause the pressure in the car to become too high. The evaporator has the potential to burst out and leak.

What causes the high-pressure switch on the AC?

In the winter, a lack of airflow across the indoor coil is the main reason for a refrigerant high-pressure switch to be on. Having a high temperature split throughout the indoor coil is one indication that there isn’t enough ventilation. Check the filter for dirt restrictions.

What causes the low-side AC pressure to be too high and the high-side pressure to be too low?

This problem could be caused by several factors, including problems with the heater or AC controls, low refrigerant levels, compressor problems, and more. Low-side high pressure and high-side low pressure in the air conditioner are signs of an air-conditioning problem.

What are the symptoms of an overcharged AC system in a car?

  • A lack of cooling or warm air is flowing from the vents.
  • The compressor is noisy or not working.
  • High-pressure reading.
  • Engine failure.

Can you drive with an overcharged AC?

You can expect your air conditioning system to not function well if there is air present and Freon is added. The compressor experiences significantly more strain when you drive your vehicle with an overcharged AC system. It may even harm the system in the long run.

That is all for this article, where we discussed the meanging, causes, and how to fix the AC low-side pressure too high issue. I hope you learn a lot from reading this article. If you do, kindly share it with others. Thanks for reading; see you around!