How Does Air Conditioning Work?


AC leakWhen it comes to working on your car, finding the right solution for your make, model and year car can be difficult.  Today there is more information available than ever about cars, and especially other people’s experience working on them through forums, chats, and question and answer type websites.  The problem is, many of these sources may not be trust worthy, or may not be specific enough to your application.  Often, a thorough understanding of the way a system should work can often help present a clear solution allowing you to fix your vehicle without having to dig through all the information available to you.  A good knowledge of the way a system works can also be extremely helpful in being able to perform an accurate diagnosis of what is going wrong.

Many systems in your vehicle are designed to operate within certain limits and for certain amounts of time.  When these systems are pushed to their limits, failures can be expected.  For example if you are constantly running your engine at the redline, it won’t be long before you have to replace bearings and piston rings.  Similarly, in the summer months, your air conditioning is often working at, or close to, its maximum capacity cooling your vehicle after it has sat in the sun or keeping it cool on warm days.  It is not surprising that most air conditioning system failures occur during the summer months.  To help you accurately diagnose your system failure and the appropriate repair, we will take some time to understand how your vehicle’s air condition system works.

The air conditioning system in your vehicle works off the basic principle that expanding gases cool as they expand.  The heart of your air conditioning system is the expansion valve where the high pressure refrigerant is allowed to expand back to a relatively low pressure, cooling it off.  This cool refrigerant then goes on to absorb the heat from the air in your vehicle and carry it outside where it is transferred to the air outside your vehicle.  This heat transfer process is done in 2 heat exchangers.  Like radiators, these heat exchangers have refrigerant flowing on the inside and air passing over the outside.  The evaporator is inside the vehicle’s cabin and is what removes the heat from your cabin air.  The condenser similarly is outside of the vehicles cabin and transfers that same heat into the surrounding air.  The other main component of your air condition system is the compressor.  Since it is the expansion of a compressed gas that creates the cooling effect, the refrigerant in your air conditioning system first must be compressed to a high pressure and cooled back down before it can expand.

Air Conditioning LinesThe refrigerant in your air conditioning system travels from the compressor, to the condenser, through the expansion valve, to the evaporator to cool the cabin air then back to the compressor.  These 4 components are connected by hoses and pipes that can contain the high pressure refrigerant.  As we talked about earlier, high temperatures push air condition equipment to its limits.  High summer temperature creates extremely high pressures in your air condition system.  These high pressures can easily push refrigerant passed worn O-rings or through very small cracks exposing new leaks.  Low refrigerant is one of the most common causes of a malfunctioning air conditioning system, especially in the warm part of the year.  As refrigerant leaks out of your air conditioning system it will slowly blow warmer and warmer air isn’t cool at all.

If your car air conditioner is blowing hot air slowly, you need to seal the leak as quickly as possible so you don’t lose any more refrigerant.  Finding a leak in an air conditioning system can be extremely difficult because when the refrigerant leaks out it is a clear gas and usually doesn’t leave any residue or evidence behind.  The easiest way to repair any leak in your air conditioning system is to add BlueDevil Red Angel AC Stop Leak for air conditioner leak repair.  BlueDevil Red Angel will not harm your air conditioning system and can remain permanently in the refrigerant.  At the leak point, a temperature differential is created activating BlueDevil Red Angel sealing the leak.  With a sealed leak you can refill your air conditioning system with the proper amount of refrigerant restoring your AC to its proper operating conditioning.

Red Angel AC Stop Leak & Conditioner

You can add BlueDevil Red Angel AC stop leak using the BlueDevil oil injector, or in purchase BlueDevil Red Angel One Shot which is a complete solution in an easy to use aerosol can.  You can Purchase BlueDevil Red Angel One Shot here.

You can also purchase BlueDevil Red Angel at any of our partnering auto parts stores:

  • Prime Automotive Warehouse
  • AutoZone
  • Prime Automotive Warehouse
  • Advance Auto Parts
  • CarQuest Auto Parts
  • O’Reilly Auto Parts
  • PepBoys
  • NAPA

Pictures courtesy of: and

2 responses to "How Does Air Conditioning Work?"


  1. Debra Russell on April 7, 2015 at 8:12 pm

    I took my car over to the Chevron station near me and my air conditioner wasn’t cooling. So they looked under my hood and said that it wasn’t just freonthat I needed. They said that I needed a compressor so I told them to put one in and they had to put in a couple of pounds of freon init so I said okay. This was last Saturday and it was cooling fine until today, Tuesday afternoon.
    I have a 2003 Honda.

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