Car Overheating When AC is On | Problem Solved!

Car Overheating When AC is On

Car ac overheating is a common problem many drivers face today, so we have broken down all you need to know about it in this article. A typical car ac, if well-maintained, is likely to run without trouble for years if minor checkups and the top-up of its refrigerator are done every two to three years. 

If your car overheats with ac on, it is a sign that it is in distress and can lead to more mechanical and economic damage. What are the signs one should look for? What are the possible reasons and solutions? Let us find out!

Symptoms Of Car Overheating When AC is On 

Let us begin the article with the most essential point, i.e., recognizing the problem. How do you know that you are experiencing car ac overheating?

It is essential to remember that these signs of car ac overheating should not be overlooked as they can lead to more severe damage to the vehicle.

Following is a list of possible reasons that your car heating up when ac is on:

Temperature Gauge Or Light 

Depending on the model of your vehicle, your car will have a particular component that measures or keeps a check on the temperature of your engine and car.

It generally tends to be a temperature gauge or a warning temperature lamp. This is highly instrumental in determining if you are driving an air conditioner overheating car.

Let us first talk about the temperature gauge and how it can help determine if you are experiencing ac overheating car. What exactly is a temperature gauge? It can be best understood as an essential dial located on your car’s dashboard and designed to measure the temperature of your engine’s coolant. This special temperature-regulating fluid runs through the engine. 

To check if you are experiencing car overheating when the air conditioner is on, keep taking note of this dial and ensure it does not go above a hundred and ten degrees Celsius, which is a clear indication that there is an issue.

You will find a warning temperature lamp in certain cars instead of the above-described dial on the dashboard. It may just be the word ‘TEMP’ or a thermometer. If this sign is blinking, it is a sign of an air conditioner overheating the car.

Car Feels Hot

The above indicator of a car overheating when ac is on corresponds to your engine’s internal temperature. This point is talking about the physical hotness of your car.

Check the surface of the ac, and if you feel that it is unusually hot while being in the drive or else, it could be a result of the car overheating with ac on.

Engine Compartment’s Ticking Sounds

Another common symptom of car ac overheating is ticking-type sounds coming from your engine compartment. How does the car heat up when ac is on, leading to these sounds?

A car’s engine oil stops being viscous if it is over-utilized, meaning if it is used more than the prescribed period making, it is incompatible with the engine. When the engine oil performs well, it will lead to lumps of increased friction, resulting in ticking sounds.

Engine Shutting Down

This is not just a particular symptom of car ac overheating but engine overheating in general. It is a loud sign of something being wrong. 

In a huge fraction of cars, the engine automatically shuts down in cases of overheating. This is a precautionary measure against further damage to the engine and ensures that the vehicle only turns on once the engine and vehicle temperature have sufficiently gone down.

Unusual Odor Or Smell

A strange odor is also a symptom of overheating with ac on. Let us talk about the why before we dive into the actual types of odor to notice,

As we know, a car’s engine is mostly metallic. It also has a few plastic and rubber components to keep it in place. These parts get affected the most in cases of overheating when ac is on or any other cause for that matter.

In case of a car overheats when the air conditioner is on, you may notice a hot smell. It can be defined as the smell of burning plastic. If you notice an unusually sweet smell coming from your car, it can be caused due to leaking coolant.

Speed Issues

 You may even go through speeding problems while you drive. How can you recognize this problem?

While you are driving, if you feel that your car is moving forward sluggishly and unable to maintain the speed limit you want, it clearly indicates that you are experiencing some mechanical issues.

Apart from car ac overheating, expanded pistons could be the reason for the same.

Steam Coming Out Of Your Engine

The clearest sign of overheating in a car is a cloud of steam coming from under the hood of our vehicle. This may be smoke or vapor. Where does it come from?

As mentioned above, leaked coolants cause car overheating when ac is on. When this leaked coolant evaporates, it can become an alarming vapor.

This brings us to the end of symptoms that indicate car overheating when the air conditioner is on. Let us keep in mind that all your senses should be alert when you are driving. You should keep your eyes, ears, and nose skeptical for any symptoms of distress that your car may be projecting.

These minor symptoms of even a car can help you get a hold of the situation before more damage is caused to the vehicle. Thus, it is essential to be vigilant to avoid problems.

Reasons For Car Overheating When AC Is On

Let us move on to the possible reasons you may be experiencing this issue. Let us take a deeper look into the various reasons for a car overheating when the air conditioner is on:

Due To An Overloading Compressor

An AC compressor overload is a common reason for car ac overheating. Let us break that down. Your ac has a compressor, the heart of the air conditioning system. It loads the engine every time the AC is switched on.

You can conduct a small test to cross-check if your car is experiencing an ac compressor overload. Check the RPM boost after switching on your AC. RPM can be described as rotations or revolutions per minute.

If the compressor falters, it will affect the accessory belt directly. It is expected to stop turning in a case like this. The car will still try turning the compressor despite the malfunctioning belt. This leads to overheating of the engine, which originates from car ac overheating!


A faulty radiator can also lead to car overheating when the air conditioner is on. Before we detail that, let us talk about the meaning of radiators. 

They are an essential part of your car’s engine and are best understood as heat exchangers. They are instrumental in cooling down internal combustion engines. This is where the car ac overheating comes into the picture.

Blockages and interferences are likely to happen in the internal pipes of your car’s radiator. This will directly have a bad effect on the flow of the coolant and air through it. This will further affect the cooling effect of the engine, which can cause overheating.

Another reason for the same can be stored dirt and rust on the component. Pipe and fluid leaks can also contribute to overheating.

A Faulty Fan

You can experience an air conditioner overheating car if your ac system has a malfunctioning fan. This fan includes several internal components, which include the fan clutch, cooling motor, etc.

If even one of these multiple sub-components has a defect, it will affect the fan’s working, leading to car overheating when the air conditioner is on.

Slowly turning fan blades, a rattling noise when the ac is turned on, or the blades not rotating are clear signs that something is wrong with your ac fan. If not checked, you can be expected the car to overheat with ac on,

Fault Cooling System

Each vehicle may have a slightly different cooling system, but let’s discuss the general components to help you identify potential causes of car AC overheating, which typically involves this system. Begin by examining the cooling fan mentioned earlier, followed by the condenser.

The condenser plays a crucial role in the cooling system, as its function is to change the cooling gas from a gaseous state to a liquid form through condensation. It should operate smoothly unless there is an obstruction or blockage within the system.

If the radiator experiences any blockages, it can hinder the condenser’s proper functioning.

Car overheating when ac is on is common if the condenser does not work well. A malfunctioning water pump can also cause the same. The described car ac overheating can result from improper heat depletion due to a broken water pump in the system.

Bad Engine Coolant Sensor

The engine coolant sensor can also be the reason for car ac overheating. This particular component is responsible for sending signals to the control module. The latter then regulates the cooling fans. A faulty engine cooler sensor is thus expected to lead to car overheats with ac on.

Coolant Leak

As previously stated, coolant is the fluid that circulates within the engine, maintaining its optimal temperature. Any coolant leaks can disrupt the vehicle’s cooling process and cause overheating when the air conditioner is used.

If you cannot pinpoint why your car’s AC is overheated, consider checking for trouble codes related to your AC system.

Use a reliable and secure diagnostic scanning tool for this task.

Consulting your local mechanic should be your next course of action if this doesn’t yield results.

Now that we have listed all the common causes of car overheating when air conditioner is on, we can move on to its solutions. 

Solutions For Air Conditioner Overheating Car

 Let us talk about what to do once it happens. Do these steps with extreme caution and care.

Clean Your Radiator

Begin by cleaning your radiator, as its crucial role in the engine’s cooling system has been extensively discussed above. Removing any blockages will ensure the unobstructed flow of air and coolant. If the radiator clamps are worn, loose, or defective, replace them, as doing so may help prevent overheating.

Wondering if you can check your radiator for leaks at home?

The answer is yes! Radiator testing kits are available and can be easily used with the help of online tutorials. If you’re uncomfortable working with your engine, you can always enlist the assistance of a professional.

Air Pressure Gauge

An air pressure gauge can be best understood as a device that measures the pressure exerted by a gas. Installing it can help you tackle your car’s ac overheating problem. What good will it do, though? Where can I attach it? 

It can be installed at any end of the radiator and can be used to monitor the flow of air through the system. It can further help in checking for leaks.

Clean And Flush Your Coolant System

As mentioned above, your coolant system is crucial in your car’s ac overheating problem. If you find out that the coolant mixture is the problem for car overheating when ac is on, flushing the system is a good idea. It will help you eliminate rust, dirt, corrosive substances, etc.

Hydrate Your Radiator

Another issue with your radiator, which can cause car ac overheating, is lack of water. 

You can do these things when you suspect a car overheats when the air conditioner is on. If you are not handy with your car or tools, it is best advised to meddle with your car. The engine is complex, and messing around without a good hand can cause more damage. In cases like these, calling a mechanic is the best bet!

Tips To Avoid Car Overheating When AC On

  1. Make it a point to check your cooling system, including the coolant one regularly. It will help you diagnose the problem before it becomes too critical and challenging.
  2. As mentioned above, the coolant mixture is a common cause of overheating when ac is on. This is why using the right coolant is extremely important. You should also change your engine’s coolant mixture every couple of years. It is said that this should be done every forty thousand kilometers. If you are making the exchange yourself, be very careful. Do the same with the recommended product with accurate concentration.
  3. In the solutions for car overheating when ac is on section, it was mentioned that rehydrating your engine is also important. It should be noted that tap water should never be used during this process. Only distilled water should be put in your radiator.

Tap water has minerals that are harmful to the engine. This is because it can cause corrosion and rust inside the radiator.

These tips do not confirm that car ac overheating will not happen at all, but it does reduce the chances of the same. Remember, precaution is always better than cure!

Car Overheating When Air Conditioner Is On In The Middle Of The Traffic 

Any problem that occurs while driving can feel extremely dangerous and scary. What should one do if the car overheats with the AC on in the middle of the traffic?

This is what you should do if you experience car ac overheating:

Step Action
Stay calm and composed; don’t panic.
Pull over safely to the side of the road, ensuring you’re not obstructing traffic.
Turn off your car’s air conditioning system immediately after stopping.
Open the car’s hood carefully, using gloves if possible. Check the hood’s temperature before touching it.
If you see steam or vapor, turn off the car entirely and wait for it to dissipate; let fresh air in.
Turn off the car but leave the key in the ignition to keep the fan running. Check for a malfunctioning fan.
Inspect your car for leaks if you’re comfortable working with it. Temporarily patch any leaks with hose tape, and tighten all clamps.
Refill your car’s radiator with water and coolant.
Visit a mechanic as soon as possible for a thorough diagnosis and permanent fix to avoid further engine issues.

Cost To Fix 

If you are experiencing car overheating when the air conditioner is on, you should go to a mechanic immediately. How much should you expect to pay to get an overheating car fixed? 

This cost is going to vary in every cause. It is subject to the reason for the car ac overheating and the area of your residence.

The cost of fixing a car ac overheating can range between a hundred to fifteen hundred dollars, depending on the severity of your vehicle’s issue.


Below are the frequently asked questions on car overheats with ac on. Let’s dig deep to know more.

Why does my car overheat when the AC is on and idling?

If your car overheats being idle, it has a broken compressor unit. If your AC is blowing hot air, then your AC is on the verge of failing and can go bad anytime.

Is it OK to drive a car with a bad AC compressor?

It’s not a good idea to drive with a broken A/C compressor. Although it is possible to drive your vehicle with a broken A/C compressor without doing repairs, it’s not wise. Because when the A/c in your car goes faulty, it can cause greater damage to other parts of the car and your health.

How often does an AC compressor need to be replaced in a car?

AC compressors generally last as long as the vehicle, but they can go bad early because of signs like bearings wearing out, seal leaks, and long-term corrosion. Even if a compressor goes faulty, it might not happen more than once in the car’s lifetime.

Why does my car run better with AC off?

A car’s AC derives its power from the compressor, which ultimately draws power from its engine, So using the AC continuously will take a toll on the car’s mileage on a given amount of fuel.

Wrapping Up

Your car overheating when ac is on may seem small, standard, and not a big deal. This is not the case at all!

If your car is showing unusual symptoms, there is a good reason and solution for the same! Cases like these should not be taken lightly as they directly correspond to engine overheating, which can lead to severe damage to the car and even explosive accidents.  

If a car overheats with ac on, follow this guide to tackle it easily!

Leave a Comment