Why does my car get hot when I turn on the air conditioner?

Why does my car get hot when I turn on the air conditioner?

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if you want to know why does your car heat up When turning on the air conditioning, be sure to read this note, where we indicate the possible problems.

Why does the car get hot when the air conditioning is turned on?

When a car engine overheats it is very damaging to the vehicle. It is a situation that must be prevented, but… What to do when the car heats up when you turn on the air conditioning?

See also: Why does my car get hot when I go slowly?

The main thing is to find out the origin of the problem that is affecting the correct operation of the engine.

Causes of car overheating when the air conditioner is on

If the vehicle only overheats when the air conditioning is on, the load on the engine may be quite high. There may be mechanical issues, such as a failed condenser, overloaded compressor, temperature sensor, or faulty fan. Or it could just be an incompetent AC system.

Below we detail the possible problems when the car overheats if the air conditioning is on:

1. Increased engine load


Your car engine can only be activated up to a certain point. If you are pushing your vehicle beyond its limits, the engine may start to overheat. Running the air conditioning increases the load that is put on the engine. If you are towing heavy loads up steep grades, the temperature may rise even more slowly.

If mechanical faults are ruled out, you may want to take a look at how you’re using your car. You may be asking too much of the vehicle you own.

2. Condenser installed in front of the radiator

With the condenser facing the radiator, cold air can be directed away from where it needs to go. Without enough cool air in the radiator, it is much more difficult to keep the engine temperature down.

Capacitor failure is possible. Dirt and contaminants accumulate on the condenser fins, which become clogged and therefore heat transfer does not occur efficiently.

3. Incompetent cooling system

If there is no problem with the condenser, you may just be dealing with an incompetent cooling system. We can blame a faulty water pump. If the water pump stops working properly, the heat cannot be dissipated as it should.

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It may happen that there is not enough refrigerant in the tank for a correct cooling function. In other circumstances, the lack of AC refrigerant could be putting more pressure on the system than is required.

4. A/C Compressor Overloaded

When the air conditioner is on, the compressor puts an extra load on the motor. If you watch your RPM when you turn on the AC you will notice this.

If the compressor seizes or the accessory belt stops turning, there is a fault that could possibly overheat your car’s engine.

5. Bad radiator fan

The cooling fan is useful in keeping the engine temperature low. If the cooling fan fails, the engine will overheat. However, you may not be aware of it when driving on the highway because the speed of the vehicle allows airflow.

This will become more apparent if your car is stuck in slow moving traffic.

6. Faulty Engine Coolant Temperature Sensor

The engine coolant temperature sensor is responsible for informing the control module when it is optimal to turn on the cooling fans. If this fails, the motor could overheat.

When the temperature sensor is not sending the proper signal, the coolant is not flowing as it should. This gets worse if the air conditioning is on.

How to fix a car that overheats when the air conditioning is on

When the vehicle begins to overheat, the problem should be diagnosed immediately. It is important to prevent the motor from overheating because the damage can be permanent. Here are the steps to keep in mind:

1. Check the coolant level

Before taking larger steps, start with the coolant level. You will most likely need to add a little more to the container.

  1. You should check the coolant when the car is cold. Hot liquid is pressurized and can cause irreversible damage.
  2. Locate the coolant reservoir. It is located under the hood, usually on the front or side of the hood.
  3. If the tank is transparent, you will be able to see the levels on the side. There should be a “Cold” and “Hot” line printed on the side.
  4. With a cold engine, the fluid should reach the Cold line. If not, you will need to add more coolant.
  5. Remove the cap and add the proper antifreeze mixture for your car.
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If the coolant level is low, you will need to check the system for leaks. Gaskets, seals, and hoses can wear out over time, allowing fluid seepage. Before adding more fluid you must repair any leaks.

2. Make sure the radiator and condenser are not damaged

If you wish to carry out a verification of the radiator and the condenser, we leave you the steps to follow:

  1. Use a flashlight. It may be dark near the radiator tank.
  2. Inspect the radiator and condenser for wet spots, which will indicate leaks.
  3. Observe the radiator core for signs of leaks.
  4. Inspect the upper and lower hose clamps on the radiator. Tighten them if necessary.
  5. Check the radiator and condenser fins and make sure they are not clogged or show damage.
  6. Open the oil dipstick to check for engine coolant leaks.

If there is damage with leaks you should repair it immediately.

3. Inspect AC Radiator/Condenser Fan

Almost all radiators today have an electric fan. With these fans, you can use a multimeter to test operation.

  1. Turn off the car engine.
  2. Locate the fuse box which is usually located under the dash.
  3. set the DCV (Direct Current Voltage) multimeter. Select the range that is best for the 12V circuit.
  4. Place the negative lead of the multimeter on the negative post of the battery.
  5. Connect the red lead of the multimeter to the contact of the radiator fan fuse.
  6. If the reading is 12V, the fuse is good. If not a blown fuse will give you a 0V reading on one side. A reading of 0 V on both contacts means that there is no power to the fuse.

Fans can get clogged by debris, check to make sure it’s clean around you and nothing is blocking or slowing it down.

4. Fill and diagnose the AC system

If the problem is a lack of AC refrigerant, fill it up. The AC system must function properly to minimize the load on the motor.

5. Connect an OBD scanner

If any warning lights on the dash are on, your code scanner can help you figure out the problem. connect your obdii scanner compatible in the port under the steering wheel.

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It will display a code or codes that can be used to tell the fault. Check the information you receive with an online trouble code library to help you troubleshoot.

6. Contact a professional

Not all car owners know how to solve certain problems, if you are not sure what the fault is, you should take your car to a professional who will tell you what is wrong.

Frequent questions

Can a faulty air conditioning compressor cause a car to overheat?

The compressor is not going to cause a direct failure that overheats the engine. However, when the compressor clutch engages without proper operation, there will be additional stress on the engine. This problem can quickly lead to engine overheating.

Can an overloaded air conditioner cause an engine to overheat?

When the air conditioning system is overloaded, the compressor may fail. Any damage to the compressor can put additional pressure on the engine. If not repaired immediately, the engine can start to overheat due to stress.

Does car air conditioning make the engine hotter?

The air conditioner puts an additional load on the engine. If the engine is already prone to overheating, having to work harder can push it over the edge. In some cases, you can prevent the engine from overheating simply by turning off the air conditioning.

Does turning off the air conditioner prevent overheating?

If there is a fault in the cooling system, the air conditioning system will not make a difference or change the problem. However, you can reduce the load on the engine by turning off the air conditioning. This simple change can give you a little more time to drive home without overheating your engine.

Conclusion: the car overheats when the air conditioning is on

At the first sign of a overheated engine , you want to take action. Your prompt attention can make the difference between fixing a small mechanical problem and having to change the engine. Wouldn’t you rather add some coolant or replace a small part than give up your vehicle for an engine rebuild?

Our guide gives you the simple steps to fix the overheating issue. Whether it’s air conditioning related or not, you should be able to get back on the road in no time.

Drafted by Gossipehículos

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