6 Reason Why Car Overheats When AC Is On And The Solution

You don’t need to go to a professional or auto repair shop to know why your car overheats when AC is on. However, with my experience, I will tell you the symptoms of car overheats when with AC on, the reasons, and how to fix it.

But, the surprising thing is that many car owners go to the car mechanic or a professional and spend hundreds of dollars just to find out why their car overheats when AC is on. And also for similar issues like engine hot ac off. But as a car owner, first, you should try to address these issues by yourself.

In fact, if your car overheats when the ac is on and idle, you should not worry because you will also get the solution for that. No matter what type of vehicle you drive, a truck or car, the vehicle overheats when ac is on the issue comes from the vehicle’s components which are the same for both car or truck.

Now, Let’s know the most common five reasons why your car overheats when AC is on and symptoms of a car overheating when AC is on.

Why Car Overheats When AC Is On

car overheats when ac is on
Why car overheats when ac is on

The most common cause for car overheating when ac is on is a failing AC compressor which increases engine load, and another one is an inefficient car cooling system. For both reasons, your car can overheat with ac on.

One of the reasons is if your air conditioner compressor adds rotational load to the car engine and if the compressor gets harder to turn, this can lead your car to overheat when AC is on.

Another reason is that the cooling system is not working properly and the air conditioner’s condenser and the water pump. Both are creating excess heat, and that’s why your car overheats when AC is on.

There can be other causes why your car overheats when AC is on. This is also possible that an overcharged AC can cause overheating of the car.

What Are The Reasons Car Overheats With AC on

If you ever notice that your car engine dashboard, and seats overheat after a few If you notice that your car engine’s dashboard and seats overheat after a few minutes when you turn on the air conditioner. And even if your car overheats when idle and AC is on, you should check the AC compressor, the condenser, and the water pump right away.

This issue happens with many cars, and these days cars run hot with ac on is a very common issue around the world. The reasons for car overheating with AC are pretty similar to car shakes when ac is on the issue. I will show some possible solutions for car overheats when AC is on below so that you can check your vehicle’s components to address the problems like this.

Here are the most common six reasons why car overheats when ac is on:

  1. AC Compressor overload
  2. Bad Cooling System
  3. Issues with Radiator
  4. Faulty Fan
  5. Defective Engine Coolant Sensor
  6. Fault in vehicle Components

1. AC Compressor overload

Car AC compressor
AC compressor in a car

The most common reason why a car overheats when AC is on is the AC multifunctioning compressor overload. When you turn the air conditioner on, the compressor needs to work with the engine, and the compressor moves the refrigerant cylinders to compress, which creates great pressure on the engine.

As we know, the car air conditioning system draws a significant amount of power from the engine. And putting a high load on the compressor that the compressor can’t handle and eventually makes your car engine overheat. A high load can damage the AC compressor or make it bad, which can prevent AC from blowing cold air. When a car engine gets heated, it makes the whole cars overheat in a short amount of time.

2. Bad Cooling System

In the car AC system, the cooling system has a very significant role. The cooling system job keeps the air conditioning’s condenser cool. When you turn on the air conditioner that heats up, the cooling system cools this down and provides cold air. If your car cooling system is clogged, the condenser temperature will rise. Therefore, when condenser heat gets too hot, the car will overheat when you turn AC on.

Another reason that occurs for clogging is if the radiator or condenser tubes get clogged over time. The tubes and corrosion or particles can cause the clogged area. You have to check this out whenever the engine temp is high with ac on. Remember, clogging is another devastating issue in the car. The radiator and condenser in the car may help you to figure out why your car overheats.

3. Issues with Radiator

The radiator helps to pass the coolant into the engine. That’s why the radiator got a significant role in your vehicle. When the radiator passes the coolant through the metallic fins to the engine, it helps a vehicle to operate properly. And radiator work can be disrupted anytime, which leads your car to overheat when ac is on.

Whether you have a faulty radiator or defunct metallic fine in your car, it’s always a good idea to check the radiator when you notice your car getting overheated when you turn on the air conditioning.

4. Fault Fan

ac condenser fan
Car’s AC condenser fan

Your car can overheat when ac is on for the engine fault fan. When there is a lack of airflow through the radiator and condenser, this problem can happen. The Engine fan could be broken or blockage in the fins or block the radiator and condenser. This problem ultimately causes the failure of the fan switch, which causes your car to overheat when ac is on and idle.

And when the car gets overheated at slow speed or idles, the engine fan can be the main reason because if the engine fan is clogged or bad, it can’t blow the air to the engine.

5. Defective Engine Coolant Sensor

Engine Coolant Sensor
Car engine coolant sensor

Engine coolant temperature sensors are rare in this case, but I have seen many cars overheat when the AC is on for this. The coolant temperature can be measured and then compared to the temperature indicator on the dashboard—the fault in the temperature sensor, which causes inaccurate dashboard indicator readings.

When it reads normal, and the temperature is rising, your engine could overheat. So you should check the functioning of the thermostat. This might be the reason why your car is having overheating issues with ac on.

To fix the defective engine coolant’s temperature sensor issue, you may need to go to a professional mechanic, or you may have to replace it.

6. Fault in-vehicle Components

Fault components in your vehicle are so common that you may have a fault in vehicle components. The fault components in your car can cause your car to overheat when AC is on. If the compressor, condenser, evaporator, and refrigerant do not work properly or as they should be, the pressure gets into the air conditioner; thus, the car temperature gets increased.

To avoid these issues, you should check these components regularly and make sure those components work efficiently. You should not forget a minor faulty component can bring problems in your car.

Tips: Whenever you bring your car to a car mechanic, always check your car’s components, the mechanic can do it for you, and they will tell you the working efficiency of your vehicle components.

These six issues are the most common reason why your car overheats when the air conditioner is on. I have seen many cars overheat when AC is off for these reasons. So, if your car overheats when the air conditioner is off, you should check these reasons. But the most common reasons for this issue are the clogged radiator and the bad water pump in the car.

Many people ask me about a specific model or brand car’s overheating issue when ac is on. A question like a car overheats when ac is on Honda civic or Jeep overheats when ac is on. But most of the car’s air conditioning system is the same whether you drive a Honda Accord, Honda Civic, or a jeep.

Solutions For Car Overheats When AC Is On

Repairing the car’s components or engine is always an expensive solution. But due to the car air conditioner system issue, repairing a car engine is not the ideal solution. There are many components in your car that cause the car to overheat when ac is on. So, Before you repair anything for this issue, you need to be certain.

Here are some solutions when car overheats with ac on:

  • Clean The Radiator
    The radiator is the grand central station for an engine’s cooling system. If your car’s radiator has been clogged, this might be the main issue for the car overheating when ac is on. If the radiator has been blocked, the radiator cannot pass the Antifreeze and water continually.
    Try to check the radiator and keep the radiator clean regularly. It would be very helpful if you could clean the radiator’s internal pipes with tools.
  • Check The AC Compressor
    The AC compressor might be the main culprit when it comes to issues with car air conditioners. If you heard any noise from the AC compressor, then check the AC compressor properly. Check the AC compressor’s wire and check the proper voltage. Of course, you have to check the damage and the clutch in the AC compressor.
  • Flush the Coolant System
    By flushing, the coolant system can fix car overheats with ac on issues in your car. Regularly checking coolant systems is good practice for every car owner. You should not avoid this too.
  • Check The Refrigerant
    The refrigerant is an essential ingredient of your car’s air conditioner. Therefore, you should be careful whenever you recharge your Air conditioner or Remove Freon from the car. Proper checking and maintaining a sufficient amount of refrigerant in the car can rescue your car from overheating when ac is on.

    Many car owners get the wrong types of refrigerant in the car, making your car overheats with ac on. If you do not recharge particular types of refrigerant in your car, this might create an issue with the car AC system. That’s why you should check the Freon level in the car regularly.
  • Check The Condenser
    The car air conditioner condenser is a radiator positioned between the car’s grille and the engine cooling radiator. Check the AC condenser first. If you see your car’s AC condenser is clogged or blocked, you need to clean the condenser right away. Bad condensers cannot work properly, which might be why your car overheats when ac is on.
  • Change the coolant mixture
    Coolant (also known as Antifreeze) is a colored liquid that is mixed with water to help regulate your car engine during extremely cold temperatures. If you want to avoid car overheating issues when ac is on, you should change the coolant every two years. Antifreeze also helps to prevent corrosion in your car and increases the durability of your car.
  • Add water to the radiator
    The radiator needs water to operate properly. That’s why you should check the radiator. If you see the radiator is dry, then add water to the radiator. The car’s water pump takes water from the radiator and moves it through the motor back to the radiator, where the cycle begins again.

What Are The Symptoms Of A Car Overheating When AC Is On

You may be thinking about what are the symptoms of a car overheating when AC is on. There are some common signs which will tell you your car is overheating when AC is on. In order to know those symptoms, you have to read with proper concentration.

Here are the most common signs of a car overheating when AC is on:

  • Car’s interior components feel hot
    If your car’s interior components get hot and you can feel it, that is the sign of the car overheating with the AC on. When you feel your car is hot, you might get some burnt smell from the car or air conditioning. If so, it tells you the car overheats when you turn the AC on.
  • Car’s temperature gauge
    Reading a car’s temperature gauge is a handy gauge to tell if your car overheats when ac is on. Your car’s temperature gauge measures the temperature of the engine’s coolant. Your car’s average temperature should be between 195 degrees and 220 degrees which you will see in your car’s temperature gauge. So, if you see your car’s temperature gauge reading higher than 220 degrees, that’s the sign of the car overheating with AC on.
  • Car engine shuts down
    If your car overheats, your car will automatically shut down no matter what causes the issue. When you turn the car’s AC on and suddenly the car engine shuts down, this indicates you have a problem with the car’s air conditioning system, which makes your car overheated.
  • A cloud of steam coming out from under the hood
    One of the most traditional ways to know your car is overheating is a cloud of steam coming out from under the car’s hood. This way to indicate whether a car is hot or not is still a very useful way. So, whenever you see clouds of steam coming out from under the hood, you should check your car’s for overheating issues.

These are the most common and useful signs which tell you if your car overheats when AC is on. Before taking any steps to your overheating car with AC on, you have to be certain about which causes this issue in your car. That’s why you should know the symptoms of car overheating when AC is on.

What To Do If Car Overheats With AC On In Traffic

Surprisingly enough, I experienced this in my life. Being stuck in traffic is always stressful and irritating. Also, the car overheats with AC on in traffic. This is worse than anything, I guess. What do you think?

Here is what should you do if car overheats with ac on in traffic:

  1. First, you should pull over as soon as possible if your car overheats when ac is on in traffic. Unfortunately, many times and in many places, you cannot pull over the car.
  2. Turn off the car air conditioner. This might help your car engine cool a bit. But, it would be best if you can turn off the car after parking and neutralize the car in a safe place.
  3. Open your car hood. A most common practice to cool the car engine is opening the hood of your car. And this is a useful way. If your car’s hood is so hot and you don’t even touch the hood. You should wait until it cools down. After your car hood gets cold, you can open it, and the steam will be gone. This is how you can cool an overheated car.
  4. Turn off the car engine but keep the key in the ignition, and as it should be on mode. This will keep the fan running, and you can hear the sound. If you notice the fan doesn’t work or is not spinning as it should be, the fan might be the main culprit for the car overheating.
  5. Wait for approximately 30 minutes. Your car air conditioner should cool down within 30 minutes. When your car engine is cold, you need to check and search for any leakages in your car.

You can get a professional to check the car properly and find out why your car overheats so fast and why your car overheats when the AC is on because it’s really a serious situation in traffic.

Frequently Asked Questions (FAQ)

Q: Can the AC make your car overheat?

Your car air conditioning can make your car overheat for defective AC components in your car, which will make cars overheat. Most importantly, your car’s cooling fan has the significant power to make your car hot so, if your car has any faulty or defective AC components, that can cause car overheating.

Q: Can a bad AC compressor cause a car to overheat?

Yes. A car AC compressor can cause overheating of the car engine. If your car AC compressor has been seized up, the belt will not be able to move properly. The AC belt connects the AC compressor clutch to the engine crankshaft, which allows the compressor to be turned via the engine’s power when activated. That’s why the belt is an important component. Without a belt, you can drive your car, but the car will get overheated after a few miles. When it comes to car overheating issues, you have to be aware of many parts of your car. A bad compressor can cause a car to overheat, and also, you should ensure that the water pump is working effectively.

Q: Is it bad to start your car with the AC on?

Starting your car with AC on is not bad or harmful for your car because your vehicle automatically shuts off every electronic component (AC, radio, and others) when you start your vehicle’s engine. Once your car engine is started, a sufficient amount of power comes back to those components again.

Q: Can a bad thermostat cause ac not to cool?

There is no direct connection between a car AC and the Thermostat. The Thermostat’s job is to regulate the amount of coolant that is recirculated back into the engine. The Thermostat has a connection to the car engine. So, it’s quite clear that a bad thermostat cannot cause AC not to cool.

Q: Can low Freon cause car to overheat?

A lack of or low Freon in a car can cause a car to overheat because when the Freon or coolant runs out, the car’s AC compressor can’t compress the Freon. That’s why air conditioning compressors produce loads to the car engine, and eventually, the whole car overheats. And similarly, your car’s AC cannot produce cool air for low Freon.

Final Words

You should always check your car’s cooling system. Car overheats when AC is on is a very common issue in cars these days. I have shared all of the possible reasons, symptoms, and solutions for fixing car overheats with AC on the issue.

If you tried all of the possible solutions in your car and haven’t got the proper If you tried all of the possible solutions in your car and haven’t got the proper solution, you need to go to a professional or service center to check the problem and get the solutions. You should not consider the car overheating issue as a simple or minor problem. That’s why if you notice your car overheats when AC is on, you should take steps or fix this issue as soon as possible.

As we already know, that car overheating issue can cost you a massive amount of money to lose. Also, car overheating can put you in great danger anywhere and anytime. So, you need to care about your car’s air conditioning to keep yourself and your family safe.

Now It’s Your Turn

I’d love to hear from you.

Which one of the problems causes your car overheat when AC is on ?

Let us know in the comment below.

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1 thought on “6 Reason Why Car Overheats When AC Is On And The Solution”

  1. Well … it’s takes about an hour of driving, then car will over heat . The air will stop blowing out of the vents, even though the fan is still working. Just got a brand new water pump and 2 thermostats , thinking maybe the first one had been faulty. Stuck in Fla. trying to get home . Yes I could take the windows and doors off the jeep and have redneck AC , but it won’t stop raining. Any ideas??


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