Automotive A/C and How it Works

In these warmer months, there is always an uptick in appointments for automotive A/C auto maintenance, and repairs. Your car or truck’s air conditioning system can be very costly when it comes to repairs, so it is crucial to your A/C system’s health that you are maintaining it on a regularly scheduled basis. 


With long, sometimes uncomfortable, Northern Virginia commutes, we need our vehicle’s A/C system to be running at optimal levels. The crew at Casey’s in Chantilly, VA are of the mind that in order to gain a better understanding of why maintenance in your car or trucks various systems is important, you should first know how those systems work.  Below, we will give brief and very simple explanations for how an automotive air conditioner operates, the warning signs of a failing system, and what you should be doing to maintain its health. 

Automotive A/C Components and How They Operate

Like your home’s A/C system, a vehicle’s system also requires a refrigerant. The refrigerant is heated and cooled during the process and done so on a continuous loop. When you turn on your vehicle’s A/C system, you activate its compressor. The compressor takes the refrigerant and compresses it at high temperatures. The refrigerant then moves into the condenser. While it is flowing through the twisting tubes of the condenser, airflow begins to cool it down so that the liquid is now prepared to enter the receiver-dryer. 


The receiver-dryer has a little reservoir installed in it where it uses desiccants to remove any water in the process. Desiccants are basically the same thing as those little packets you find in a box of new shoes. After the moisture has been drawn out, the refrigerant then flows from the receiver-dryer through an expansion valve. The valve allows the fluid to expand which reduces pressure on the refrigerant thereby allowing it to move into the evaporator. 


The evaporator’s job is to absorb heat, and it is the real MVP of the entire system. The refrigerant enters the evaporator coil where a fan over the outside of the evaporator blows cool air into the passenger compartment, while the refrigerant continues its way back towards the compressor where the process continues in a looping fashion. 


Think of it as like your body when you sweat. When you’re hot, sweat is released that moistens the surface and cools you down as it evaporates. A/C systems are fundamentally the same.

Warning Signs to Watch Out For

It’s 8:00 AM and you’re heading into work. You turn on your A/C without giving it another thought until 5 minutes march by and you realize that what you’re feeling isn’t cool, it’s just air. That could be a telltale sign that your system needs sine refrigerant to be added into it. Given that refrigerant doesn’t exactly evaporate, this could also mean your system has a leak.


We have all dealt with it. The dreaded puddle in our parking spot or driveway. Sometimes it’s just A/C condensation that has dropped to the ground. Other times it can be oil from the engine. But, if your A/C is blowing hot air and there is an oily-like substance leaking from the underside of your vehicle, chances are your A/C system has a leak. 


You’ve turned on the unit, but it sounds… different. Grinding or squealing sounds coming from your A/C system while running could be a sign of compressor or clutch issues. While it may be easy to ignore, we suggest you get your vehicle into the shop as soon as possible. Running a dying compressor might cause additional damage.

So, what can you do to maintain your A/C and avoid future costs? 

Look for debris on your vehicle – Finding leaves, dust, etc. on the gills of the grill under your windshield? Remove that stuff so it cannot get sucked into the A/C system and clog it up. The same thing goes for under your hood. Make sure you don’t have that debris under there, especially near the condenser.


Regularly run your system, even in the winter – By turning the A/C on once a week for at least 10 minutes, you will help it to maintain the refrigerant’s gas pressure as well as keep the compressor working properly. 


Replace your air filter – This is an often-overlooked component. Many are told they have dirty filters after their vehicle has been serviced, but this often goes undone by choice. That is a surefire way of clogging up the system. When you bring your vehicle into Casey’s, our team will provide you with a free 42-point inspection of which will include photos of your air filters. If they are dirty, have them replaced!


Make sure to schedule professional service – Your vehicle’s A/C system should be recharged every 2 years. The professionals at Casey’s Automotive in Chantilly, VA and Sterling, VA will do this by refreshing the refrigerant and lubricating the moving parts you read about earlier. 

Casey’s Automotive: Expert Auto Maintenance Services in Chantilly, Virginia 

We understand how having to bring your Chantilly, VA vehicle in for regular auto maintenance can sometimes be a hassle, but our aim is to keep you as informed as possible so that you can avoid costly future events. Maintaining your car or truck’s A/C is essential, and we are happy to help our customers by sharing our knowledge. If your A/C is blowing hot air, contact a Casey’s location today for an A/C inspection!

The best referral you can get is from a neighbor.