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Why is my BMW Car Air Conditioning Not Cold?


BMW AC system control panel

Car AC not blowing cold air?

Has your BMW stopped blowing cool air from the car's ac system? Are you not sure how to get your ac system back to work properly? Let's clear some things up and learn a bit about auto ac repair and air conditioners in general.


Why is my AC on but blowing hot air?


There are several potential reasons why your car's air conditioning may not be producing cold air. Some possible causes include:

  1. Low refrigerant levels: If the refrigerant levels in your car's air conditioning system are low, the system may not be able to produce cold air. This could be due to a leak in the system, or it could be the result of the refrigerant being improperly charged during a previous service.

  2. Faulty compressor: The compressor is responsible for compressing and circulating the refrigerant in the air conditioning system. If the compressor is faulty or not functioning properly, the system may not be able to produce cold air.

  3. Damaged or worn-out components: If any of the components in the system are damaged or worn out, the system may not be able to produce cold air. This could include the evaporator, the condenser, or the expansion valve.


AC system diagram

Air conditioning system


The basic components of an AC system include:

  1. Compressor: The compressor is responsible for compressing and circulating the refrigerant in the system. It is typically powered by the engine's drive belt.

  2. Condenser: The condenser is a heat exchanger that is responsible for releasing the heat absorbed by the refrigerant as it passes through the system. It is usually located in front of the radiator and has fins to help dissipate the heat.

  3. Evaporator: The evaporator is a heat exchanger that is responsible for absorbing heat from the air inside the vehicle. It is usually located inside the vehicle, in the dashboard.

  4. Refrigerant: The refrigerant is a chemical that is used to transfer heat from one location to another. It is circulated through the system by the compressor and absorbs heat as it passes through the evaporator.

  5. Expansion valve: The expansion valve is a device that controls the flow of refrigerant into the evaporator. It helps to regulate the pressure of the refrigerant as it enters the evaporator, ensuring that it can absorb as much heat as possible.


AC system compressor

AC compressor


The air conditioning (AC) compressor is a key component of the AC system. It is responsible for compressing and circulating the refrigerant, which is the chemical that is used to transfer heat from one location to another. The compressor is typically powered by the engine's drive belt and is located at the front of the engine.


AC system


When the AC system is turned on, the compressor starts to operate. It pumps the refrigerant through the system, compressing it and increasing its temperature. The refrigerant is then passed through the condenser, which is a heat exchanger located in front of the radiator. The condenser releases the heat absorbed by the refrigerant as it passes through the system, cooling the refrigerant down.


The cooled refrigerant is then passed through the expansion valve, which is a device that controls the flow of refrigerant into the evaporator. The expansion valve regulates the pressure of the refrigerant as it enters the evaporator, ensuring that it can absorb as much heat as possible.


The AC evaporator is a heat exchanger located inside the vehicle, in the dashboard. It absorbs heat from the air inside the vehicle, cooling it down. The cooled air is then blown into the cabin of the vehicle through the air vents.


As the refrigerant passes through the system, it absorbs and releases heat in a continuous cycle, cooling the warm air inside the vehicle. When the AC system is turned off, the compressor stops operating, and the refrigerant stops circulating through the system.



BMW air conditioner vents

How much does it cost to fix the AC of a car?


The cost to repair a car's air conditioner can vary widely depending on the specific AC system problem that needs to be addressed. Some common AC repairs, such as recharging the system with refrigerant or replacing a faulty compressor, can cost several hundred dollars. More complex repairs, such as replacing the evaporator or a new AC compressor, can cost significantly more.


Other factors that can affect the cost of AC repairs include the make and model of the vehicle, the age of the AC system, and the availability of parts. In general, repairs to newer, more complex AC systems tend to be more expensive than repairs to older, simpler systems.

It is difficult to give a precise estimate of car AC repair cost without knowing the specifics of the problem and the vehicle.



Auto AC repair machine


What is the most common AC repair?


One of the most common air conditioning (AC) repairs is recharging the system with refrigerant. The refrigerant is the chemical that is used to transfer heat from one location to another in the AC system. It is circulated through the system by the compressor and absorbs heat as it passes through the evaporator.


Over time, the refrigerant level in the AC system can drop due to leaks or other problems. When this happens, the AC system may not be able to produce cold air, or it may not function at all. Recharging the system with refrigerant is a relatively simple repair that can be performed by a mechanic.


Other common AC repairs include replacing a faulty compressor, replacing the expansion valve, and replacing the evaporator. These repairs are typically more complex and can be more expensive than recharging the system with refrigerant.


In conclusion, to diagnose and fix the problem, it is best to have a mechanic check your car's air conditioning system. They will be able to identify the specific cause of the problem and recommend the necessary repairs.

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