Air Conditioning Service

Auto Service: Air Conditioning, A/C

The air conditioning system in a car is serviced when freon gas gets low or when the system does not work.

How often should service be performed for the car:

A recharge of the AC freon gas will not be required until the car has quite a few years or miles. Usually this becomes apparent when the air blows hot from the vents. A fully charged system should reduce ambient temperature downwards of forty degrees. As the air conditioning system ages freon will seep out through small leaks where parts are joined together and sealed with rubber o-rings (a circular gasket). These o-rings begin to dry out and cannot give an air tight seal. The system will still reduce temperature even with half the freon required, just not as well. Therefore as the car ages, a recharge of the system every three years is normal.

What are the symptoms of faulty Air Conditioning for the car:

If this recharge lasts a short period of time, there is a more significant leak which needs to be diagnosed and repaired. Usually, one of the lines, the condenser or the evaporator will develop a hole where the freon will leak much more rapidly. The air conditioning system will also not work if a component has failed mechanically. The compressor is the most common failure item. The pulley on the compressor is in constant motion, even when the air conditioning system is not in use, and will wear out over time. The compressor also contains the most moving parts within the system, so breakdown at some point is expected. In newer cars with advanced climate control, sensor and computer problems are quite common. If a sensor stops working or if it measures incorrectly (either pressure or temperature) the system will stop working.

How air conditioning works in a car:

Air conditioning provides a large amount of comfort when driving. Ambient temperatures and heat generated by the engine can create a very uncomfortable cabin for passengers. Air conditioning does not provide cold air, instead when the system is working well will take the heat out of the air inside the cabin. The freon under high pressure will pass through a valve either called a thermal expansion valve or an orifice tube, which allows the freon to rapidly expand. This drop in pressure creates a drop in temperature. The freon then passes through tubes in a radiator looking device inside the cabin called an evaporator core. The air inside the passenger cabin is pushed through this evaporator core before it exits the vents and has the heat taken out as the freon seeks to regain surrounding temperature. This process also takes all the humidity out of the air in the cabin (think of the evaporator core as a cold can of soda with condensation). This process of drying air also makes the defrosting of the windows in the winter time much easier. The air conditioner will be active when defrost is commanded even with the heat running. This will take moisture out of the air and quicken the defrost of windows.

What can happen if this service neglected for the car:

Neglect of the air conditioning system can lead to some problems. For the most part, a non-functioning air conditioner means no relief from high temperatures and humidity, and accordingly this lack is more problematic in areas of the country where sustained high temperatures are common. However, in colder climates, lack of air conditioning will cause longer times to defrost or defog windows before driving safely. In some cases, mechanical failure may lead to other problems in the car. A seized compressor can break the serpentine belt and leave the car without a power steering pump, an alternator and a water pump. Finally, freon is an ozone depleting agent. Any leaks in the system are detrimental to the environment.

What does the typical air conditioning service cost?

  • Estimated cost for diagnosis and recharge (most common) = $100-$250
  • Estimated cost if minor leaks are detected = $200-800

Most automotive service professionals can perform this service. Keep in mind, pricing will vary by location and your vehicle make and model. Save time and money by using Openbay to compare pricing and book an appointment with a service center in your area.

Service article written by an ASE Master Technician