Car AC Stops Working When Hot Outside – Causes & Solutions

If you have ever been driving on a hot summer day and suddenly your car AC stops working, you know how frustrating and uncomfortable it can be. Unfortunately, this problem is all too common, and it can be caused by a variety of issues so it’s important to address the problem as soon as possible, not only for your own comfort but also to prevent further damage to the AC system. In this article, we will explore the most common causes of car AC stops working when hot outside, as well as some possible solutions to get your AC system up and running again.

Before diving into the causes and solutions, it is important to understand how a car’s AC system works.

How a car AC system works

A car’s air conditioning (AC) system is designed to cool the air inside the vehicle to provide a comfortable environment for the occupants. Here is a step-by-step explanation of how a car’s AC system works:

Refrigerant

The AC system uses a refrigerant to cool the air inside the vehicle. The refrigerant is a special chemical that is capable of absorbing and releasing heat as it changes from a gas to a liquid and back again.

Evaporator

The evaporator is a heat exchanger located inside the vehicle. Its job is to absorb heat from the air inside the car and transfer it to the refrigerant. As the refrigerant absorbs heat from the air, it vaporizes and becomes a gas.

Compressor

The compressor is a pump located under the hood of the vehicle. Its job is to pressurize the refrigerant gas and pump it through the system. The high pressure of the refrigerant gas increases its temperature and makes it more effective at releasing heat.

Condenser

The condenser is a heat exchanger located under the hood of the vehicle. Its job is to release the heat absorbed by the refrigerant gas and cool the refrigerant back down to a liquid state. The condenser releases the heat by transferring it to the outside air.

Expansion valve

The expansion valve is a small valve located between the evaporator and the compressor. Its job is to control the flow of refrigerant and maintain the proper pressure in the system. As the refrigerant passes through the expansion valve, it expands and cools, causing it to lose pressure and temperature.

Cycle

The AC system works by circulating the refrigerant through a closed loop system. The refrigerant absorbs heat from the air inside the car at the evaporator, is pressurized and heated by the compressor, and releases the heat at the condenser. The expansion valve then reduces the pressure and temperature of the refrigerant, allowing it to absorb more heat at the evaporator. This cycle continues as long as the AC system is running, cooling the air inside the car and providing a comfortable environment for the occupants.

Causes why Car AC Stops Working When Hot Outside

There are several potential causes for a car AC system to stop working when it is hot outside. Some common reasons include:

A leak in the refrigerant system

A leak in the refrigerant system can cause the AC system to stop working. The refrigerant is a vital component of the AC system, and if it is leaking, the system will not have enough refrigerant to cool the air inside the car. A leak in the refrigerant system may be due to a problem with the hoses, fittings, or other components of the system.

Faulty compressor

The compressor is a vital component of the AC system and is responsible for pressurizing the refrigerant and pumping it through the system. If the compressor is not functioning properly, it may be unable to pressurize the refrigerant, causing the AC system to stop working. A malfunctioning compressor may be caused by a variety of issues, including a failure of the compressor clutch, a problem with the compressor bearings, or a malfunctioning compressor control valve.

Clogged cabin air filter

The cabin air filter is responsible for filtering the air that enters the car’s interior. If the filter is clogged, it can restrict the flow of air into the car and cause the AC system to stop working. A clogged cabin air filter can be caused by a variety of factors, including dirt, dust, and pollen.

Electrical issues

Electrical problems can also cause a car’s AC system to stop working. Some possible electrical issues that could cause this problem include a faulty relay, a damaged wiring harness, or a blown fuse.

Lack of maintenance

Proper maintenance is important for the proper functioning of a car’s AC system. If the system is not regularly maintained, it can cause issues such as a clogged cabin air filter or low refrigerant levels. These issues can cause the system to stop producing cool air. Regular maintenance, including changing the cabin air filter and checking the refrigerant levels, can help prevent these issues and ensure the AC system is functioning properly.

Steps to fix car ac stop working when hot outside

Identify the cause of the issue: The first step in fixing the problem is to determine the cause. Some potential causes of a car’s AC system not working when it is hot outside include a malfunctioning compressor, a leak in the refrigerant system, a faulty thermostat, a lack of maintenance, or a clogged cabin air filter.

Check and replace the cabin air filter: To fix the issue, you can check the cabin air filter and replace it if it is dirty or clogged. The cabin air filter is typically located behind the glove compartment or under the dashboard. To replace it, you will need to locate the filter housing and remove the old filter. Once the old filter is removed, you can install the new filter according to the manufacturer’s instructions.

Check for leaks: To check for leaks, you can visually inspect the AC system for any signs of damage or wear, such as cracked hoses or loose fittings. You can also use a refrigerant leak detection kit to check for leaks. If you find a leak, you will need to repair the system and refill the refrigerant.

Have the system professionally serviced: If you are not comfortable troubleshooting or repairing the AC system yourself, you can have it professionally serviced by a mechanic. A mechanic will be able to diagnose the issue and fix it properly. They will also be able to check the system for any leaks or faulty components and repair or replace them as needed.

Replace faulty components: If the issue is due to a faulty component, such as a malfunctioning compressor or expansion valve, it may be necessary to replace the part in order to fix the problem. This can be a more expensive solution, but it is necessary if the component is damaged beyond repair. A mechanic will be able to diagnose the issue and replace the faulty component as needed.

Tips To Prevent You From Car AC Stops Working When Hot Outside

There are several tips you can follow to help prevent your car’s air conditioning (AC) system from stopping working when it is hot outside:

Regularly maintain the system: Proper maintenance is important for the proper functioning of a car’s AC system. This includes regularly changing the cabin air filter and checking the refrigerant levels. By keeping the system well-maintained, you can help prevent issues that may cause the system to stop working.

Avoid using the AC system excessively: Over-using the AC system can put extra strain on the system and increase the risk of it malfunctioning. To help prevent this, try to avoid using the AC system excessively, especially when it is very hot outside. If possible, try to park in the shade or use the vehicle’s vents or windows to cool the interior instead of the AC.

Keep the vehicle well-ventilated: Allowing air to circulate through the vehicle can help keep the interior cool and reduce the need to use the AC system. To do this, you can park in the shade and use the vehicle’s vents or windows to ventilate the interior.

Avoid using non-approved refrigerants: Using the wrong type of refrigerant can damage the AC system and cause it to stop working. To help prevent this, it is important to use the refrigerant specified by the manufacturer and avoid using non-approved refrigerants.

FAQS

Q: Can a low refrigerant level cause the AC to stop working?

A: Yes, a low refrigerant level can cause the AC system to stop working. The refrigerant is responsible for absorbing heat from the air inside the car, and if there is not enough refrigerant, the system will not be able to produce cool air.

Q: How often should I have my car’s AC system serviced?

A: It is generally recommended to have your car’s AC system serviced every 1-2 years or every 20,000-30,000 miles, whichever comes first. However, this can vary depending on the specific make and model of your car, as well as your driving

Q: How much does it cost to fix this issue?

A: The cost of fixing a car AC system that stops working when it is hot outside can vary depending on the cause of the issue and the extent of the repair needed. Some potential repair costs could include:

  • Cabin air filter replacement: $10-$50
  • Refrigerant recharge: $50-$150
  • Compressor replacement: $500-$1,500

It is important to note that these costs are estimates and may vary based on the specific make and model of your car, as well as the location and labor rates of the repair shop. It is recommended to get a detailed quote from a mechanic before proceeding with any repairs

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