All You Ever Wanted To Know About Your Car's Air Conditioning

There you are, stuck in traffic on a hot summer day and your air conditioning isn't working. This can be a frustrating and uncomfortable scenario. Yet, it can be handled so you can get back to driving in comfort. The first step to making sure your air conditioner is running properly is understanding the system itself and how the automotive A/C system keeps the vehicle's cabin cool. Here is a rundown of everything you need to know about how your Toyota's A/C system works:

The Components Of An Automotive A/C System

Automotive air conditioning has been around for decades. Yet, the system being used in most vehicles today is only about thirty years old. It consists of five basic parts:

  1. Compressor
  2. Expansion valve
  3. Evaporator/blower
  4. Drier
  5. Condenser

How The Components Work Together

An automotive A/C system keeps the cabin cool by circulating a refrigerant. It's a highly thermally-active substance that is pressurized and then quickly expanded, which makes it cold.

AC Diagram

All automotive air conditioning works on the principles of compression and induction. Here's how the components work together:

1. The Pump Pressurizes The Refrigerant In The Vehicle's A/C Lines

The compressor is mounted on the engine. It is powered by the accessory/serpentine belt. When active, it pressurizes the refrigerant in the vehicle's two A/C lines: The low pressure line and the high pressure line.

The line going into the compressor is the low pressure (return) line. The line coming out of the compressor is the high pressure line. The refrigerant is always in gas form when it flows through the compressor.

2. The Condenser Cools The Refrigerant

Next, the refrigerant, in gas form, flows through the high pressure line from the compressor to the condenser. The condenser is a type of radiator. It takes the highly pressurized refrigerant through a series of switchbacks around which air flows. This process cools the refrigerant. This cooling action also liquifies the refrigerant, which then goes to a drier.

3. The Drier Separates The Water Vapor From The Refrigerant

The drier separates water vapor from the refrigerant. This process exists to reduce the potential for the liquid refrigerant to freeze. Water vapor can enter the system through condensation, even though the system is closed, and cause the refrigerant to freeze. The drier acts as a failsafe for that.

4. The Expansion Valve Expands The Refrigerant

From the drier, the refrigerant heads to the expansion valve. The controls within the vehicle that turn the air conditioning on and off will open and close the expansion valve accordingly. When open, the valve allows the refrigerant to suddenly expand (depressurize). The sudden expansion causes the refrigerant to get very cold. The expanding refrigerant is sent through the evaporator, which is another type of radiator. The evaporator is usually located behind the glovebox. As the refrigerant passes through it, the blower fan pushes air over the evaporator. The cool air is then pushed into the passenger compartment.

5. The Refrigerant Is Depressurized

At this point, the refrigerant is depressurized and has returned to gas form. It returns back to the compressor to complete the loop.

Important A/C System Maintenance Tips

If you have issues with Toyota's your A/C system, some or all of the following tips may help you find and address the problem:

  1. Remember that he refrigerant used in automotive air conditioning is considered a hazardous substance by governing authorities. It is illegal for anyone but qualified technicians to remove refrigerant.
  2. It's easy to fix a moldy or musty smelling ventilation system. All you need to do is run the A/C system and spray deodorizing spray into the vents. You can find detailed step-by-step instructions here.
  3. In smaller cars, running the A/C at high speeds (over 75 mph) is more fuel efficient.
  4. When troubleshooting a failed A/C system, check the following parts:
    • Refrigerant level (the number one cause of automotive a/c problems is a refrigerant leak)
    • Compressor
    • Evaporator
    • Condenser
  5. You can save a lot of money on OEM replacement A/C parts by ordering from us. We carry OEM Toyota A/C parts at discounted prices.