How does my cars a/c work

Ever wondered, “How does my cars A/C Work?”

 Just like the rest of your vehicle, your A/C is made up of many components. All of which need servicing and some attention occasionally, Just like your tyres and engine. 

All car and machinery air conditioning systems are sealed systems with a high-pressure side and low-pressure side. The fluid that is used in the system is called refrigerant. Your car’s AC is made up of 5 key components, plus hoses, o rings, seals, valves, pipes and electrical wiring to keep it running.



The compressor is the workhorse of the car air conditioning system. When the aircon system is turned on, the compressor pumps refrigerant vapour under high pressure to the condenser.


A condenser changes the high-pressure refrigerant vapour to a liquid. The vapour is condensed to a liquid by the force of high pressure created by compressor, which generates heat. This heat is then removed from air, flowing through the condenser.  (Hence why it’s important to make sure your condenser is not blocked up)

Receiver Drier

Now liquid refrigerant moves to the receiver-dryer. This acts as a filter for the liquid refrigerant, removing any moisture and other containments that may have leaked into the refrigerant. Desiccant bag driers are also becoming popular as the drier of choice for European vehicles, in place of the receiver drier.

Expansion Valve (also known as a TX valve)  & Accumlators (ophrius tubes)

What the thermal expansion valve and accumulator both have in common is that they prevent any moisture from leaving the evaporator and causing havoc in the system.  Both also use a type of desiccant to clean up the refrigerant before air is blown out from the AC system.


Now, how are the accumulator and expansion valve different?

Expansion valve opens and closes according to the level of coolness you’ve set. At the same time, it also moves on its own based on its sensing bulb to ensure that the refrigerant is cool enough for the temperature outside the A/C.

Orifices tubes, on the other hand, don’t move. You are stuck with the same size until the time comes for you to change to a new orifice tube. The compressor and also several additional parts to ensure that the flow is adjusted to your demand and need.


As the cold low-pressure refrigerant is passed through the evaporator, it vaporises and absorbs heat from the air in the passenger compartment. The blower fan inside the passenger compartment pushes air over the outside of the evaporator, so cold air is circulated inside the car.


The compressor then draws in the low-pressure refrigerant vapour to start another refrigeration cycle. The refrigeration cycle then runs continuously and is regulated by the setting of the expansion valve.


Why get your AC serviced regularly?

The air conditioning system in your car is made up of many different components, so regular maintenance can prevent expensive and avoidable repairs.  Over time, your vehicle will lose its refrigerant – up to 10% per year. O Rings and seals shrink, rubber hoses can come porous. Not to mention the state of your condenser and evaporator with all the dust that’s about.

Condenser and evaporator servicing in North West NSW is particularly important, especially in the current conditions. A dirty evaporator or condenser will create excessive moisture build up, causing components to corrode and leak – not to mention restrict air flow.


 We recommend getting your car air conditioning serviced every two years, and machinery annually  to keep your system at peak performance.


We recommend Cars and 4WDs have their vehicles serviced every 2nd year, or annually in extremely dusty condition (farm vehicles).

We recommend working trucks and machinery be serviced at least annual – with other components (like condenser) cleaned regularly.   We can also provide Fleet servicing solutions.


To Read more about why you should your A/C serviced check out this link