There are many aspects of the AC system that ever driver must understand. Read on for more information, issues and other facts regarding the automobile AC system.
Regardless of your manufacturer, air conditioning works the same in all cars. All makes have components that apply the same principles to ensure that you enjoy cooler air and more bearable driving conditions.
We made a complete guide to all things air conditioning. Whether you’re simply interested in how the system works or need some tips on a failing air conditioning, you may want to read on for more.
How the AC on your car works
Before we can get into identifying a failing air conditioning and what could case this failure, it is important that you understand how the system works. Most people may think that AC systems create cool air, this is not quite correct.
Instead, the AC in your car cools the air by removing the hot air and moisture thereby making the cars environment more suitable for the driver.
The AC systems’ functioning depends on a refrigerant which must effectively change properties when subjected to different physical changes like pressure. Simply put, the air conditioning in your car has two roles
- Cooling the air entering through the passenger compartment
- Reducing the moisture content inside the car
Major parts of your AC that allow its proper functioning
Your air conditioning works by applying some principles including evaporation and condensation, followed by cooling and expansion. Instead of boring you with the thermodynamics and physics behind it all, we will explain these principles in conjunction with the parts that allow the air conditioning system to work.
This is the belt-driven pump attached to the engine that acts as the processor of the entire system. It has a magnetic clutch at the front to activate the compressor when it receives power.
When active, the compressors’ role is to compress and afterward transfer refrigerant gas. In other words, it pumps refrigerated gas to the condenser in a loop. This refrigerant is responsible for cooling the hot air, which is then released back as cool air.
A notable pressure difference helps divide the AC system into two parts: the ‘discharge’ high-pressure side and the ‘suction’ low-pressure side.
The compressor sucks low-pressure gas from the evaporator and accumulator, compresses it to a high-pressure nature, and sends it to the compressor.
The condenser receives high-pressure refrigerant gas from the compressor. It is where the refrigerant gas changes to a liquid form. This component is quite similar to a radiator and it is mounted on the engine's radiator.
High-pressure driving in the gas from the compressor is responsible for the change of state to a liquid. This process generates a lot of heat, usually removed by the air circulating outside the condenser.
Also known as the thermal expansion valve, this component depresses the refrigerant liquid back to a gas. Cars that use a receiver drier rely on the thermal expansion valve while those with an orifice tube utilize and accumulator.
Either way, this part is usually found between the evaporator and condenser. These parts coordinate to maintain your system's correct pressure and temperature, calculating the right amount of refrigerant that can circulate the system.
Receiver drier or Accumulator
Both these components have a desiccant material that takes up moisture from the air, the second function of the AC system in your car.
Difference between these two AC systems
Orifice Tube and Accumulator System
This system has the orifice tube before the evaporator and the accumulator before the compressor.
The orifice tube is charged with restricting the refrigerant flow and altering the pressure from high to low thereby converting the refrigerant from a liquid to a mist. In the accumulator, a desiccant bag effectively removes the moisture from the refrigerant before it gets to the compressor.
Expansion Valve and Receiver-Drier System
Unlike the system above, the receiver/drier is between the in line filter kit and the expansion valve before the evaporator. Like an accumulator-based system, the receiver/drier has a desiccant to take up moisture from the air before reaching the evaporator.
Another notable difference between two systems is the positioning of the parts. While they play the same role of removing moisture from the air, the receiver/drier I usually found on the high-pressure side, unlike the accumulator on the low-pressure side.
This is the part located right behind the dashboard. Your evaporator's job is to deliver cold air to the passenger compartment.
The refrigerant we’ve been speaking about us commonly known as Freon. It is also known as R1334 and is widely used in many vehicles. However older models used the refrigerant that was eliminated from use in the AC systems due to its highly pollutant nature.
TIP: ever driver needs to know that turning on the AC will reduce the miles per gallon on your car.
Because the process of removing heat and moisture from the car's atmosphere requires more energy than you would normally use, your engine carries an extra load and thereby consume more petrol.
Common issues with your AC system
Having a properly working AC is wonderful, especially when seasons change and summer rolls around.
However, there are many instances when your AC system will not deliver the much-needed cool breeze. Here are some of the most common AC issues many drivers might experience.
Air is blowing but it isn’t cold
Nothing is more frustrating than turning on your AC, and you meet a blast of warm air. In addition to the annoying driving conditions, an AC system blowing warm air could mean safety issues.
You might be experiencing an issue with your AC blowing warm air for several reasons.
- First, you might turn on the AC and meet a warm blast of air. Sure, it takes some time for the air in your car to get cold, but there will be some instances when
- Second, the ac might start out cold and get warm. You might think the AC system is working in many instances, but then you notice the air gradually getting warmer. Some of the reasons for this may be a clogged expansion valve, a Faulty compressor clutch, or a blown fuse that prevents power from reaching certain parts and leaks within the AC system.
- Lastly, the air from your AC might not be as warm as it used to be. Sometimes the air from your AC might not be exactly warm, but it isn’t as cold as it once was. Most times, clogging, damage to some of the components or even failed parts or fuses lead to a decline in the coldness of the air.
Musty odor coming from your AC
Several issues with your AC system could trigger the gym sock smell. A dirty or old carbon filter and a moldy evaporator case are the most common reasons for this smell issue.
Odd smells from your vent aren’t the only effects of mold or mildew in your AC system. The residual mold and mildew growing from excess moisture might inhibit air from the system and cause a weak airflow.
Unfortunately, no warning or indicator lights will alarm you when there’s an issue with your AC system.
Some common causes of AC system failure
Leaking refrigerant is one of the biggest culprits of AC system failure. These leaks can occur anywhere in the components and often lead to many issues, some of which we mentioned above. Car owners must learn to check for leaks if they suspect an issue.
Damaged or worn parts are also a major concern as they influence how well your AC system will function. Wear and tear is often responsible for most of the issues with the AC.
Lastly, problems with the electrics, like a shortened fuse, are usually the other cause of AC system failure. The electrical components must work safely and normally so that the entire system can coordinate properly.
Otherwise, an error with the electrical system will trigger the AC system to shut down to prevent improper function, damage, or unsafe conditions for operation.
What is an AC bypass pulley?
The AC bypass pulley, unlike a more traditional AC system, is a free-spinning pulley that replaces the AC compressor on the automotive engine. If your AC system fails, bypassing the AC compressor is a cheaper and more efficient way to fix the issue.
In fact, a bypass pulley spins with less resistance than the factory AC. However, replacing your AC compressor with this pulley will mean no more air conditioning.
A failing Bypass pulley
These systems usually fail when your car experiences issues with wear and tear or improper installation. you may notice screeching sounds, squealing or even grunting noises from the hood when your engine is running. Some of the main causes of a bypass pulley failure include the following.
- Worn or corroded bearings inside the system
- Poor or improper installation of the belt could result in premature pulley failure.
- Installing the wrong belt could also lead to pulley stem failure. These systems often rely on factory-manufactured serpentine belts.
Consequences of AC Bypass pulley failure
Once the serpentine belt breaks from the system failure, you will experience power loss in your engine accessories including the alternator and pump. Continued running on this failure will reduce power output and impact gas mileage.
The AC system is an important component for good driving conditions. This system follows a standard design across manufacturers, and you could crack a window to allow air circulation. Still, an AC enabled car is the best way to cool down when driving during hot weather efficiently.
However, the AC system is prone to issues that could interfere with proper function. If you experience these issues, you should see a professional for further insight.