5 Reasons why Car Overheating When Air Conditioner Is On (Car Overheats With AC On)

Perhaps there is not a person who would feel comfortable on the hottest day, sitting in a stuffy car. Not only does it cause serious discomfort, it also affects concentration - when it's hot in the car, what kind of concentration can we talk about? Fortunately for us all, technological progress has given us air conditioners in cars. They help us to overcome even the most terrible heat, but at the same time, in case of malfunction, they can also cause a lot of trouble. 

Don't worry if your car is overheating once the air conditioner is turned on. It doesn't indicate any manufacturer-based fault mainly. Here are some factors that are most likely why your car is overheating when the air conditioner is on.

The purpose of a car air conditioning system is to cool and dehumidify the air inside the vehicle. This can make the ride more comfortable for passengers, as well as help to prevent fogging of the windows and condensation on other surfaces. Additionally, cooling the air can help reduce stress on the engine and other components, potentially extending the life of the vehicle. Many systems also include a heating function, which can be used to warm the interior on cold days. Some newer vehicles even have air conditioning systems that automatically adjust the temperature and ventilation based on the outside temperature and the amount of sunlight present.

Reasons Why Is Your Car Overheating When Air Conditioner Is On

The cooling system of the car is a rather complex structure, which consists of many elements, and each of them performs an important function. It is impossible to say for sure which system malfunction caused the breakdown and, as a consequence, overheating. There are many reasons why your car overheats when the air conditioner is on, but we will give the most popular ones in this article. If you notice that your car is overheating when the air conditioner is on- try to check each of the points that are described in the article. If none of them will be effective - you should go to a qualified mechanic to fix the problem of overheating. 

Some fault within the air conditioner


Probably the most apparent reason behind the sudden heat up. Some fault with the Air Conditioner includes major mechanical defects in the AC shaft or even leakage of excessive AC gas.

Whatever the reason is, the fault in the main AC panel can eventually overheat your car whenever the AC is turned on. If continued, this can also overheat the main engine body of the vehicle.

How To Diagnose Your Car Air Conditioner?

If your car's air conditioner isn't working, then you'll want to diagnose the problem as soon as possible. There are a few things that could be causing the issue, so it's important to narrow down the possibilities. Here are a few ways to diagnose your car's air conditioner:

1. Check the air conditioner's fuse. The fuse could be blown, which would prevent the air conditioner from working.

2. Check the air conditioner's compressor. The compressor is responsible for circulating refrigerant, so if it's not working, then the air conditioner won't work either.

3. Check the air conditioner's evaporator. The evaporator is responsible for cooling the air, so if it's not working, then the air conditioner won't be able to cool the air.

4. Check their conditioner's hoses. If any of the hoses are leaking, then that could be why the air conditioner isn't working.

5. Check the air conditioner's thermostat. The thermostat controls how much cool air is produced, so if it's not working properly, then the air conditioner won't work properly either.

Faulty fan setup


There are two factors within a car making sure that the engine is always in a cooled-down state. We all have learned in elementary causes that resistance of any sort within the motors generates heat, dragging down the performance efficiency of the engine in the end.

The engine is cooled down through a constant flow coolant and fresh air intake through the fan set up to avoid such an outcome. But what if the fan setup is faulty or clogged? It will surely aid the overheating of the car instead of reducing it.

How To Fix An Air Conditioner Faulty Fan Setup?

If your air conditioner has a faulty fan, there are a few things that you can do in order to fix it. First, you will need to ensure that the power to the unit is turned off. Next, you will want to remove the front panel of the air conditioner so that you can access the fan. Once you have access to the fan, you will need to unscrew the old fan and replace it with a new one. Finally, you will want to screw the new fan into place and turn the power back on to the unit. By following these steps, you should be able to fix a faulty fan in no time.

Poor radiator maintenance


The complete car cooling operation is dependent upon one component in particular. Yes, we are talking about the radiator system. The primary function of the radiator is to make sure that the car engine always remains calm and the temperature is maintained at a workable level.

This is done when the coolant is transported through the radiator system right into the surroundings of the engine. You must have seen thin metallic fins around the engine of your car; that's the radiator fins providing a path to the coolant. If the AC is working fine, chances are pretty prominent that the overheating issue is associated with the radiator and its maintenance.

How To Keep Your Radiator In Good Working Order?

It is important to maintain your car radiator in top condition to prevent overheating and engine damage. Here are a few tips on how to properly care for your car radiator:

1. Check the level of coolant regularly and add more if necessary.

2. Flush the radiator and replace the coolant at least once a year.

3. Inspect the radiator hoses regularly and replace them if they are cracked or leaking.

4. Check the radiator cap for proper sealing and replace it if necessary.

5. Keep the radiator clean and free of debris.

Following these simple tips will help keep your car radiator in top condition and prevent engine damage and overheating when the air conditioner is on.

Outdated cooling system

You might be surprised by hearing this, but there are some car models out there that still don't have a proper coolant-based car cooling system. These models usually have lower price tags or those manufactured by not credible manufacturers.

When buying the car of your dream for which you have worked this much, you must make sure that the cooling system is not outdated at all. You might think it is not essential, but in the long run, ignoring it can end you up in a severe car accident.

Compressor overloading


Last but not least, compressor overloading. In simple words, when you put too much work pressure on the compressor, even more than what it was designed to bear ideally, your car will overheat. This usually happens when you overuse the air conditioner of your vehicle.

The compressor is like the heart of any AC system. It compresses air and releases it simultaneously to generate a pleasing and cool stream of the air we all enjoy. But when the compressor is subjected to overloading, it completely forgets its function and starts increasing the car's temperature instead of reducing it.

Lack Of Coolant


Your car's air conditioner is designed to keep your car cool and comfortable in hot weather. The system relies on a mixture of Freon gas and lubricating oil to function properly. If there is not enough Freon in the system, it will not be able to generate the cold air necessary to keep your car cool. In addition, if the system is low on lubricating oil, it can cause damage to the compressor. As a result, it is important to keep your car's air conditioning system topped off with Freon and lubricating oil to ensure that it continues to work properly. If you notice that your car's air conditioner is not working as well as it should, or your car is overheating when the air conditioner is on, make sure to have it checked out by a qualified mechanic. They can add more Freon and oil to the system as needed to get it back up and running properly.

How To Fill Your Air Conditioner With Coolant

Most car air conditioners use a Freon-based coolant. Freon is a colorless, odorless gas that is compressed into a liquid for use in car AC systems. The Freon is then circulated through the system by an electric pump.

Over time, the Freon can leak out of the system, causing the air conditioner to stop working, and as a result, forcing your car to overheat. If this happens, you will need to add more Freon to the system.

Here is a step-by-step guide on how to fill your car air conditioner with coolant:

1. Locate the low-pressure port on your car's AC system. The low-pressure port is usually located near the front of the engine, on the passenger side.


2. Remove the cap from the low-pressure port.

3. Connect the Freon can to the low-pressure port.

4. Slowly open the valve on the Freon can, allowing the gas to flow into the car AC system.

5. Continue adding Freon until the pressure in the system is back to normal.

6. Replace the cap on the low-pressure port.

7. Start the engine and turn on the air conditioner to check that it is working properly.

If you are unsure of how to properly fill your car air conditioner with coolant, consult a professional mechanic or AC specialist.

Final note

We hope that now you understand up to some extent what are the five prominent reasons behind your car getting overheated every time you turn the air conditioner on. It's better to get your vehicle checked up as soon as possible if you are already facing such an issue.