AC system and why you should care


You like the fact that whenever you step into your car to go anywhere, in summer, you do not have to bother much about the heat outside. What has made your bothers go away? Cars are still made of metal and except high-end cars, we still do not have the kind of innovations for our mass market offerings that can keep the heat from entering the car’s cabin. Then how is it that you are still not bothered as much as you should be? The reason for that is the Air Conditioning system that is present in your car. Over the years, it is among the top reasons as to why would you buy a car or anyone else suggests you to buy one. It runs on same basic principles as the Air Conditioning system kept at your homes, just that it is packaged in a tighter manner so that it can go along with the car to any place you want to head to.

Air Conditioning (AC) systems have been present on cars for quite some time now. So now, we do not just talk about ACs when we talk about cars, we talk about the next stage. This next stage is called Automatic Climate Control AC (we would refer to it as Climatronic AC for the sake of shortening it for further use in the article). Early AC systems were the kind that would keep cooling/warming the cabin irrespective of how the users felt about the same. They were turn on/turn off switches than anything else. Today’s Climatronic ACs are the kind which are more than just turn on/turn off switches. All they ask you to do is set the temperature and they handle the fan speed and the amount of cooling/heating that you have asked for. This is the reason why such systems have started appearing on mass market cars. Such systems have become more of a necessity than just a luxury item.

How does the AC system work in my car?

The working of AC system is simple, but before we go there, we would like to clear one thing. The air that AC throws out and makes you feel cool is not cold air but hot air. The working of the AC system will tell you how the cold air from the system feels the way it does. When you turn the AC on, its compressor comes on. The compressor compresses the refrigerant which raises its temperature. The refrigerant then flows through a condenser (it looks like the radiator). Then it passes through receiver/dryer where all impurities and moisture are removed. Then the refrigerant passes through expansion valve where it loses its pressure and temperature. It then heads to the evaporator (placed inside the dashboard of your car) which gets cold and drops the temperature of the refrigerant even further while removing moisture from it. A fan then blows the cool air out and voila! You get to enjoy cold air on burning days.

That sounds complicated. What all components does it have?

Most AC systems, except really advanced ones (have not got to try one yet) have the following components:

  • Compressor
  • Condenser
  • Accumulator or Receiver/Dryer
  • Expansion valve/Orifice tube
  • Evaporator

Apart from these major components, there is the refrigerant, some hoses and refrigerant charging ports.

What do these parts do? How do I know which one has failed?

Naturally the next question would be for you to understand what these major parts do and how to know which one might have gone wrong when your car’s AC system starts malfunctioning. So, here goes:

    • Compressor: Its job is to pressurize air and sense temperature changes through an electrically-operated clutch (you operate it by changing AC settings). If the refrigerant leaks, there is noise from AC unit or it behaves erratically (or does not work at all), chances are compressor has gave way.
    • Condenser: This component is responsible for turning the hot refrigerant gas into liquid. It is usually mounted in front of the radiator and the air passing through it cools down the hot refrigerant gas. It looks a lot like a radiator and is also referred to as mini-radiator. If there are leaks, fans and/or tubes appear corroded, clogged or damaged, or AC does not perform up to the mark, chances are the condenser has failed.
    • Accumulator: It is responsible for trapping the harmful particles, moisture and liquid that are present in the refrigerant, preventing them from reaching critical AC components like compressor. It is accompanied by an orifice tube. In case you spot an expansion valve, you are encountering a receiver/dryer. Additional functions of accumulator over those of a receiver/dryer are control and monitoring the refrigerant entering the evaporator and storing excess refrigerant and preventing it from entering the condenser. A sure shot way of telling that accumulator has failed is when you find moisture on windows and/or defroster is unable to remove moisture from windows (in conditions when you should not find moisture on windows and glass).
    • Expansion valve/Orifice tube: This monitors the pressure and temperature of your car’s AC system to determine the amount of refrigerant that should enter the evaporator. Orifice tube may also contain a mesh filter to trap contaminants from circulating in the system. Only a technician can tell if the orifice tube/expansion valve has become dirty or clogged.
    • Evaporator: It cools air and removes moisture. Air has to pass through evaporator before it can circulate in the car as evaporator as the last component through which air goes.

Anything I should be taking care of?

First, anytime the AC system is opened for repair, the Accumulator will have to be replaced. Same goes for the Receiver/Dryer. Secondly, if it is recharging of the AC system that needs to be done, make sure it is done by qualified personnel only. Lastly, do get the cabin air filter checked for any potential issues while the system has been opened and being inspected.

When should I get my car’s AC system checked?

Anytime you feel your car’s AC is not functioning properly, be it taking too long to cool down the cabin or the air being thrown out not cool enough, just take your car to a workshop to get the AC system checked. A good time to get the AC system checked is also when you outside smell starts filtering inside the cabin even though the windows have been rolled up completely.

How often do I need to get the AC recharged?

When you feel the AC is not cooling the car’s cabin as much as it needs to. Usually, such an occasion is rare and a few users also go through the entire ownership phase of their particular car without even having to get the AC recharged. Also, remember that whenever your car’s AC is not able to cool the way it used to, there is trouble around the corner. It is because the refrigerant level go down and AC system being a sealed unit, such an incident cannot take place until something has gone bad. Whatever it may be, a small leak or failure of a component, do not wait and get the AC system checked as soon as you can.