Car AC Stops Working When Hot Outside – Why & What To Do?

Besides the problem of car ac turns on and off randomly, sometimes, your car air con blows warm air, driving you to wonder why your car AC stops working when hot outside.

The blend air door doesn’t switch from the heat to cold air. The problem can be fixed easily, but it can cause a costly repair. Read our article for some tricks to protect your AC in the summer.

Air Conditioning System Explain

Car AC Stops Working When Hot Outside

Before getting to the answer to the question, why does my AC not work when it’s hot outside? Let’s find out how each component of the AC system functions.

Air Compressor

The compressor is in charge of compressing the gas. The refrigerant is first in the status of low temperature, low-pressure gas.

When inside the compressor, it’s converted into high temperature, high-pressure gas. Suppose something is wrong with this component; the AC wont work when it’s hot outside.

Condenser 

When the high temperature, high-pressure gas moves from the compressor to the condenser, the condenser will perform like a mini radiator with the help of the condenser fan on top to emit the heat out.

At this stage, the refrigerant condensation happens and transforms into a low temperature, high-pressure fluid.

Dryer

When the refrigerant is frozen, it can block the expansion valve. There’s a dryer/ receiver to filter it through the desiccant to remove the moisture and prevent the liquid refrigerant from freezing.

Expansion Valve

The expansion valve decides how much coolant will go through the system. The coolant at this stage will expand, decreasing the temperature and pressure.

A faulty valve also can lead to the issue of my car ac stop working when it’s hot outside.

Evaporator

The evaporator absorbs the heat from the refrigerant and reduces it to 32 degrees. It’s the temperature for the coolant evaporator and becomes gas again.

This low pressure, low-temperature gas comes back to the compressor, and the cycle starts again.

Reasons For Car AC Stops Working When Hot Outside

Air Conditioning System Explain

The main reason is pressure changes. High temperatures outside can force the coolant to expand, or maybe a temperature sensor is malfunctioning.

These factors render the car AC to stop working. One stop-gap is to exude some coolant in the low-side pressure. Also, it’s best to periodically do the AC maintenance.

Refrigerant Leakage

It’s one of the most common reasons when car AC not cooling in hot weather.

Since the refrigerant keeps circling and when it turns to gas status again, it’s difficult to tell where the leakage originates exactly.

The moisture can get inside your cooling system through the leaking spot and mix with Freon, causing an acidic combination.

It can lead to AC corrosion and further damage. The problem now is even more serious than just car AC doesn’t cool.

If the refrigerant leak is small, it’s possible to use the leak seals.

However, when you have a terrible coolant leak or don’t know what to do, bring your automobile to the auto repair shop for a visual inspection and professional repairs.

Faulty Compressor

The AC compressor is in charge of moving the coolant at first; if it doesn’t work properly, so does the heat transfer process. Lack of use is the main reason for a bad compressor.

When you don’t use your cooling system for a long time, it’s understandable why your car AC doesn’t work when it’s hot outside. Therefore, it’s suggested to run it for 15 minutes every couple of weeks.

A stuck compressor clutch also can damage the compressor and lead to the car ac stops working when it’s hot outside. If it’s stuck “on”, your AC will keep running.

In case it’s stuck “off”, the compressor will be disengaged. Consult with the automobile service to diagnose the problem and have proper solutions. Sometimes, it’s better to replace the compressor than to rebuild it.

Condenser Issue

The condenser plays an important role in keeping the air cool by taking the humid air and sending it outward. If your car AC struggles in hot weather, it can signify a broken condenser.

The condenser is behind the front grille, creating a chance for the debris to come inside and block the lines.

Liquidating the blockage in the condenser coil is not a big problem. However, if your condenser is in greater damage, you need to replace it.

Electrical System Problems

An electrical issue can lead to a car AC not cold when it’s hot outside.

You need to disassemble the mechanism to figure out the root of the problem. It can be a blown AC fuse, a faulty switch, battery voltage, or control module issues.

Should you have some knowledge about electrical systems, it’s not difficult for you to fix them. However, you should troubleshoot the problem immediately.

Putting it off can cause acid buildup and serious damage. Then, you need to be aware that AC doesn’t work when it’s hot outside car, and seeking help from experts is recommended.

Broken Cooling Fans

One more reason that you can think of when AC doesn’t work when it’s hot outside the car is the broken cooling engine compartment fans.

The fan blade assists the system in reducing the heat and moving the refrigerant. Therefore, the cracked one can affect the process of cooling.

The causes for this improper work are various, such as an electrical short, blown fuse, or road debris damage. Replacing is the only remedy for your cooling system.

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

Expel The Air Before And During The Drive

It’s better to emit the warm air out of your vehicle before driving to avoid car aircon not cold during hot weather; otherwise, you will be trapped in an extreme heat box.

Scroll down the rear windows and keep opening and closing the front windows for one minute. During the drive, it’s advised to open the rear windows for 30 seconds to expel more air.

Set The AC To Low Mode

You can prevent the situation of car AC not blowing cold air when hot outside by using it at low mode to have good air temperature.

When you set it at high mode, it will take the air from inside the car, which is usually hotter than the outside one which it’s supposed to draw from.

Time To Drive

If you drive at the sunniest time of the day, more strain will be on your cooling system. Therefore, your car AC doesn’t work on hot days. You’d better drive in the cool mornings or evenings if possible.

Change The Components

The car air conditioner can’t keep up on hot days as the AC works overload in the summer. Change the components such as clogged filters to make sure it works efficiently.      

Maintenance Service

Booking a regular maintenance service to avoid the situation of car AC not working in hot weather and other problems such as car ac smells like pee.

Bring your vehicle to the repair shop regularly. Professional mechanics can check and find out the heat-related issues, preventing them from happening in the first place.

Conclusion

Reasons For Car AC Stops Working When Hot Outside

Now you understand why your car AC stops working when hot outside and how to troubleshoot the exhaust issue.

The better you treat your vehicle, the fewer problems you will have with your cooling system. Remember to apply our tips to save your air-con in the summer.

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