Symptoms of a bad or failing car air conditioning system

Since the sun’s rays can increase the temperature felt in the car interior by up to 15 ° C (59 F) compared to the temperature felt in the atmosphere, the air conditioning system plays an extremely important role in the comfort of the driver and passengers.

Nowadays, the air conditioning system of the car is a priority for most car manufacturers, this being one of the standard equipment of the cars.

In time, the functioning of the air conditioning has to suffer and requires periodic revisions, the most common intervention being the refilling of the installation with refrigerant

The car air conditioning works according to the same principle as the room air conditioning, with the mention that the rotation of the compressor is given by the rotation of the engine.

Vehicles are equipped with two types of AC: manual or automatic. The differences between the two are given by the type of order, the automatic one being much more convenient and efficient, but also more expensive.

What are the most common problems with the car air conditioning system?

  • The AC compressor does not start
  • The air temperature is not low enough
  • The airflow is low
  • The air conditioning smells bad
  • The AC system is noisy
  • The refrigerant is low or missing

Refilling with refrigerant

The most common problem and the simplest in the air conditioning is the decrease in pressure of the refrigerant or even the complete draining of it. In general, the problem is solved by a specialized car service, by refilling the AC system with refrigerant.

Although the most common cause of the lack of refrigerant is the passage of time (on average it is recommended to check the entire installation annually and refill every 2-3 years), sometimes the system may have other problems, such as broken pipes, AC radiator cracks, losses on various components (valves, compressor, condenser, etc.).

These problems can be identified by using a special fluorescent gas, which is introduced into the system and marks the areas where the gas is leaking.

Another consumable of the AC installation is the oil necessary for the operation of the compressor, which also will be changed when a problem with it is found.

What are the causes of a failing air conditioning compressor?

First of all, the AC compressor is subject to wear as it starts and stops constantly whenever we turn on or off the car air conditioning.

With the passage of time, debris or dust deposits on the air conditioning system may cause the air conditioning compressor to fail.

Older components of the air conditioning system (expansion valve, evaporator, etc.) can clog the air conditioning system and create overpressure at the compressor level. The lack of lubricant inside the compressor and its operation without oil can cause major mechanical defects.

What are the most common symptoms of a defective air conditioner?

In most cases, when the air conditioning compressor is worn out it gives us some warnings. The most common are:

Indefinite Noise

If indefinite or strange noises are heard when starting the air conditioning, it is preferable to pay attention to the AC compressor. The noise is due to the deterioration of the bearings or its internal components.

Hot air instead of cold air

When the compressor is failing, it can no longer ensure the normal flow of refrigerant in the air conditioning system and therefore the air entering the passenger compartment will become increasingly hot, even if it is set to a much lower temperature.

Fluid leakage 

The compressor consists of several parts, including its own bearings. If the compressor bearings are worn out, it no longer ensures that the fluid is prevented from leaking when the refrigerant is pressurized and thus we encounter the fluid leaks.

The compressor clutch is blocked

The clutch ensures that the compressor is connected to the engine via a transmission wheel and allows it to operate. Therefore, the clutch locking causes the air conditioning compressor to stop working.

AC condenser radiator

Due to the poor positioning, between the front bumper and the engine cooling radiator (it is mounted here to cool as best as possible), this radiator breaks most often because it is the first radiator and it stops many stones and impurities from it. road.

A little tip, when you go to the car wash in summer, ask the one who will wash the car to insist on this radiator because the dust is thermally insulating and will not let the radiator do its job. This radiator is made of aluminum and theoretically can be repaired/welded but most often such a repair is not efficient because if you repair the radiator in one place, it will give up soon in other places.

Dehumidifier filter

The dehumidifier filter removes the moisture from the AC system to protect the compressor and it is also responsible for the rapid demisting of the windshield because it gives a dry air that saves us from a misted windshield. It is necessary to replace it at every intervention on the system (when changing the radiator, a compressor, a pipe, etc.), or every 2 years.

If this filter is clogged, it is a common cause of the air conditioning malfunction system because it clogs the system on the high-pressure side and in such cases we reach pressures above 30 bar and can break a pipe or the radiator could break due to too high pressure.

The cabin fan

If this does not work, of course, you will have no cold air in the car. This can be easily seen because you will no longer have ventilation although you order it. If it does not work on the first fan speed, check the maximum fan speed because it is possible to operate only this way – this happens when the fan resistance fails (the resistance that can be changed separately from the fan and that fails most often due to overheating caused by a dirty cabin filter).

Tips for maintaining the AC system

  • First of all, it is recommended to check the air conditioning system annually. Thus, any malfunctions can be identified early and remedied.
  • Also, changing the cabin filter in time and cleaning the entire installation helps prevent debris or dust deposits and prevent the appearance of bad smell.
  • Start the air conditioner at least weekly, even in winter. The components of the air conditioning compressor will lubricate and thus reduce the risk of damage.
  • Before filling the installation with refrigerant, it is recommended to clean the entire air conditioning system with special cleaning equipment.
  • The way of cleaning the air conditioning installation is done according to the car and the type of installation. Generally, to get rid of the unpleasant odor, a special cleaning spray can be used, which will be “blown” on the condensate drainage channel or through the cabin filter area (which will be taken off).
  • Refill the installation with refrigerant at least every 2-3 years to avoid lowering its pressure.

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