You love your car A/C when it’s keeping the cabin cool in the heat of the summer. But do you know how the A/C system works or how to maintain it?
This guide has all the details you’ll need to hopefully recognize problems before they become major ones, and to keep your vehicle’s A/C in good shape.
How Does a Car A/C System Work?
Believe it or not, there is no ice machine inside your car A/C system. That cool air you feel is basically just hot air that has had the heat removed from it through a series of events that are too complicated for this article.
When you turn on your air conditioning, the compressor compresses the system refrigerant, lowering the pressure and temperature of the refrigerant.
While the refrigerant is flowing through the condenser, it is losing heat to the atmosphere. The refrigerant then typically goes through the receiver/dryer to remove contaminants and moisture from the refrigerant.
Now it is time to go through the expansion valve. In the expansion valve, the refrigerant loses pressure and temperature and enters the evaporator, chilling the evaporator as it enters.
The evaporator is like a mini radiator inside the dashboard. The airflow is blown through the chilled evaporator, cooling and removing moisture from the air. The ventilation system then puts that cool and dry air into the passenger compartment.
Although you feel that cool air while your car A/C is trying to give you cold air, the A/C system is in fact working very hard.
How Often Should My A/C Be Inspected?
There is not a set timeframe for a/c inspections- it depends on how the system is performing. When driving your vehicle, are you cool and comfortable with all the airflow of the a/c on? If the answer is “Yes, I am as cool as a cucumber” you have no need for an a/c inspection.
Now, do you fall on the “my a/c isn’t cold enough” side of the spectrum to “my a/c doesn’t work in the heat”? Don’t fret.. stop in for an a/c Performance Check and we will have you back on those stifling summer blacktop, cooler than ever.
How Often Do I Need My A/C System Recharged?
Modern air conditioning systems do not need to be recharged regularly, or on a set schedule, typically it will be years before you need to do one. You will probably know it is time.
Signs your A/C might need a recharge are (1) warm air coming from the vents or strange smells from the vents, (2) a refrigerant leak, and (3) an A/C clutch that disengages – we will cover all of these potential symptoms below!
What Are the Parts of a Car A/C?
In order to keep your cabin cool, your A/C relies on many working parts. Let us take a closer look at the parts of the A/C system, and how they work together to give you that welcomed blast of cool air.
What is the A/C Compressor?
The compressor is the heart or brain of every A/C system. It controls the temperature output by electrically operated clutch.
This clutch is engaged and disengaged with each manipulation of the temperature control or when the HVAC module detects the set temperature has been reached. If ambient air temperature drops below programmed value, compressor clutch may not engage.
Signs Your A/C Compressor is Worn
- Oil or refrigerant leaks (a professional can use special dyes to determine if there is a refrigerant leak)
- Strange noises under the hood while A/C is on
- A/C operation is erratic or fails
What is a Compressor Clutch?
The compressor clutch is a special electromagnetic clutch that disengages and engages the compressor cycle before the compressor comes on. The compressor clutch turns the compressor on or off upon request.
Signs your compressor clutch is failing:
- Poor A/C performance
- Can’t turn A/C on and off
- Clutch will not engage
What is an A/C Condenser?
Think of the A/C condenser as the master of converting hot refrigerant gases to a liquid form. The condenser is mounted at the front of your car or truck, typically in front of the radiator.
Ambient air from the outside flows through the condenser, condensing and cooling the hot refrigerant gas, and into a cool liquid refrigerant.
Signs of a Worn A/C Condenser
- Leaks
- Clogged, corroded, or damaged fins or tubes.
- Poor air conditioning performance.
What is a Receiver/Drier?
The receiver/drier is found on vehicles with a thermal expansion valve. It is essentially a safety net responsible for trapping and preventing damaging debris and/or moisture from getting to the compressor and other critical components of the A/C system.
You should replace your receiver/dryer at the time of any A/C system work, or if the system has been contaminated with moisture or debris, and a technician detects impaired performance of the receiver/dryer.
Symptoms of a Worn Receiver/Drier:
- Poor air conditioner performance.
- Moisture on glass and/or inability of defroster to remove moisture from glass and windows.
What is an Accumulator?
An accumulator is like a receiver/drier but only on vehicles with an orifice tube. If you have an accumulator, you do not have a thermal expansion valve.
The accumulator:
- Controls how much refrigerant can enter the evaporator
- Stores extra refrigerant so that it cannot damage the compressor
- Filters debris and helps get rid of moisture in the A/C System
You will need to replace the accumulator if the A/C system is opened for repair or if a technician says there is moisture or debris harming your accumulator’s performance.
What is a Thermal Expansion Valve / Orifice Tube?
The orifice tube or thermal expansion valve is between the evaporator and the condenser. It continuously monitors the pressure and temperature of the A/C system and determines exactly the amount of refrigerant that can be safely sent to the evaporator.
If too much or too little refrigerant enters the evaporator you could have a serious problem.
An orifice tube may have a fine mesh screen to prevent contaminants from getting in the rest of the system.
Sign’s you may need a new orifice tube or thermal expansion valve:
- Poor A/C system performance
- A technician has determined it is dirty or clogged
What is an Evaporator?
An evaporator is located behind your dash and is included in your A/C system responsible for cooling cabin air and removing moisture! The evaporator will cool because it contains low pressure refrigerant running through it.
Since the evaporator can already absorb heat because of its role in the A/C, the temperature of the vapor refrigerant is so low that that it will absorb heat from the cabin air.
Thus, when the evaporator is tool for the air to be blowing out in your car, and it feels cold refreshing air hits your face from the vent, it is working properly!
Symptoms of a Worn Evaporator:
- Low Poor Performance from your A/C System
What is the Clutch Cycling Switch?
The clutch cycling switch controls the compressor with regard to the pressure in the accumulator which keeps the evaporator from freezing.
Most cars can blow air as low as 60 degrees, but temperatures in the evaporator core can be cold enough to freeze the entire evaporator core entirely.
Thus the purpose of a clutch cycle is to ensure the evaporator does not reach glacial types of temperatures.
Symptoms of a Failing Switch:
- Evaporator freezing up
- Evaporator does not get cold enough
What is Refrigerant?
Refrigerant (commonly known by the DuPont trade name Freon) is a specially designed cooler that can switch from a liquid to a gas and back again. Refrigerant absorbs heat and releases it, leaving cool air behind.
Different devices – your home refrigerator, home A/C system, or vehicle – may use different refrigerants. They may or may not use the same refrigerant.
What Are The Difference Types of Automotive Refrigerant?
Automotive refrigerant is either R-12, R-134a, or R-1234yf. Different refrigerant type have different charge hoses, so find out what type is in your vehicle in earlier models.
- R-12: R-12 is the original chlorofluorocarbon (CFC) Freon that was used in car A/C systems until the mid-1990’s. After the EPA learned it depletes ozone, it was banned. Vehicles that were manufactured pre-1995 probably use refrigerant R-12. You can retrofit R-12 systems to R-134a systems.
- R-134a (HFC-134a): Your vehicle probably uses R-134a (also called HFC-134a). R-134a came out to replace R-12 once it was discovered it had dangers to the environment. While R-134a is safer than R-12, and it is what most vehicles use, it is still not the safest refrigerant for the ozone. The manufacturer recently phased it out.
- R-1234yf (HFO-1234yf): In order to phase out R-134a, manufacturers developed R-1234yf (also called HFO-1234yf), which is a hydrofluoric-olefin refrigerant. R-1234yf is more environmentally friendly refrigerant. It should be in automobile manufactured after 2021 although you may find it in earlier manufactured models.
What is a Refrigerant Charge Port?
A refrigerant service port is that point where new refrigerant are added to the system during an A/C system recharge or where you can remove refrigerant from the A/C system. There is a service port on the low side and high side A/C lines.
A/C recharging services should only be performed by properly equipped, certified, and qualified persons. The EPA (Environmental Protection Agency) regulates that anyone who services automobile air conditioning systems while handling refrigerant be EPA Section 609 Certified.