When a car’s air conditioning system stops working, the first culprit is often low refrigerant levels. However, failing AC compressors can just as easily leave you fighting the summer heat. So how can you tell if your car’s AC compressor is going bad?
Before we dive into the signs of an AC compressor failure, let’s answer one of the most common questions we get from customers:
What Is An AC Compressor?
An AC compressor is an important part in the car’s air conditioning system. In the words of many repairmen, an AC compressor is the heart of an AC system.
In simple terms, an AC compressor is a pump which creates the heat by putting the air conditioning refrigerant under extremely high pressure.
The AC compressor is called a pump because both increase the pressure on a fluid and both can transport the fluid through a pipe. As gasses are compressible, the compressor also reduces the volume of a gas.
Liquids are relatively incompressible; while some can be compressed, the main action of a pump is to pressurize and transport liquids.
The AC compressor consists of 2 ports, an inlet and outlet, or ‘suction’ and ‘discharge’ respectively. The suction port is always the larger diameter hole.
Refrigerant is ‘sucked’ into the compressor, compressed, and ‘discharged’ through the outlet, headed for the condenser. Inside the compressor is a complex series of passageways, valves, bearings, and other components.
How Does Auto Air Conditioning Work?
You might look at the air conditioning compressor as the heart of the air conditioning system in your car. In essence, the AC compressor performs for the system the same function that your heart does in your body — it provides the circulation of a precious fluid, the refrigerant, through the air conditioning system.
The compressor also compresses the refrigerant from a gaseous state to a fluid state, sending it to the condenser that acts as a “heat-exchanger” removing the heat from the refrigerant. From there, the refrigerant goes to an expansion valve or “orifice tube,” where it returns to its gaseous state.
An accumulator removes moisture from the refrigerant, and it is then transferred to the evaporator in the cabin of your vehicle, usually under the dash. There the cold refrigerant cools the air that passes by and through the evaporator, which resembles a small radiator. The cooler, drier air is then sent out the vents into the interior of your car via a fan. Ah, no sweat.
Common Signs Of A Bad A/C Compressor
If you have a bad A/C compressor, symptoms will eventually become evident. You’ll find you have one or more of these common signs:
#1. Unusual Noises And Vibrations.
When your car’s air conditioning system makes unusual noises, this often indicates an AC compressor problem.
Unlike refrigerant leaks, this is a sign of a mechanical shift somewhere in your car’s air conditioner. One of the most active parts within your vehicle AC system is the compressor—making it a likely culprit.
#2. Insufficient Cooling Or Uneven Cooling.
When there is a problem with the compressor, it may not be capable of maintaining the proper pressure or flow to cool the cabin.
#3. Leaking Refrigerant.
If you see a puddle of fluid below your vehicle when the AC is on, it is likely that the compressor is leaking. Several different issues can cause this, so it is best to take your car in for service if you notice this problem.
#4. Compressor Clutch Issues.
Just like a manual transmission, the AC compressor has a clutch. This clutch connects to your vehicle’s engine to draw power from it.
The compressor only uses the power when it needs it, but if the AC compressor clutch or its pulley gets stuck, the compressor will not work because it won’t be getting any power. The clutch itself cannot be replaced. If it seizes up, you have to replace the compressor.
#5. Unpleasant odors.
A sweet yet chemically smell might be detectible under the hood when the engine is running.
Related Post: Why Does My Car AC Smell Bad?
#6. Increased fuel consumption.
While it’s likely minor, your car may burn more gas since you need to run the A/C more to keep up with vehicle cooling.
#7. Damaged Wire.
When you do the maintenance at home, you may notice damaged wiring of any sort. It is a bad ac compressor symptom. Damaged wiring presents a huge safety concern because it can easily lead to an electrical fire.
When an AC unit is exposed to electrical problems, it can lead to the compressor receiving too much or too little voltage. This quickly damages the compressor and results in the replacement of a new AC compressor.
These are a few signs that may indicate that your AC compressor is bad. If you are experiencing any of these problems, it is best to take your car in for service as soon as possible. Replacing a bad AC compressor can be a costly and inconvenient process, so it’s important to spot the signs early on. By being aware of these common symptoms, you can take action before it’s too late and avoid a costly repair bill.
Consequences Of Ignoring A Bad AC Compressor
Of course, the most noticeable consequence of leaving your car’s compressor unrepaired is that driving conditions are more uncomfortable. It gets more humid inside, plus the heat can be unbearable. But there are other consequences too:
- Other A/C parts can get damaged because the system has leaked out the refrigerant and oil, straining the system and starving it of lubricant.
- The serpentine belt could break while you’re driving, and that could lead to a loss of key systems like power steering.
- It can increase repair costs significantly since additional repairs could be required.
- Your car is worth less than it could be if you decide to sell it.