In the scorching summer heat, nothing beats the cool breeze of air from your car’s air conditioning when traveling outside. But what happens if the AC chokes up midway or the condenser at the front starts rattling? While a defective car AC is a hassle already, the buzzing and knocking sounds from the compressor on top of it ruin the whole driving experience.
Besides the silent hum, an unusual or unsettling sound from the AC compressor is a sign of concern that you must investigate. Before you take it for a mechanic’s check-up or have it replaced with a brand-new AC system, you need to know what’s causing all the ruckus. We’ll help you identify the noise source along with ways to quiet a noisy car AC compressor.
To quiet a noisy car AC compressor, you first must distinguish the type of noise it produces. Loud vibrations and squealing compressor noise only require lubrication or a serpentine belt change. As for car AC compressor grinding noise, securely fasten the compressor mounting bolts. If you hear loud buzzing or hissing sounds, consult a professional.
Diagnosing a Faulty Car AC Compressor – Why Is It So Noisy?
Compressors are considered the backbone of an air conditioning system that pumps refrigerant through the pipelines with extremely high pressure. For an automotive air conditioning system to operate effectively, it must maintain a high pressure in the refrigerant lines while being completely sealed off from the outside environment.
Any breach or change in the pressure can result in AC system failure, which further leads to excruciating noise. Here are some common reasons for a faulty car AC compressor:
Unusually high temperatures outside can affect the performance of your car’s AC. If you feel a sudden thrust of cold air followed by a warm air breeze inside the car cabin, it’s a failure on the compressor’s part. The sudden shift from cold to warm air may also indicate a leaking refrigerant. But if the refrigerant lines seem tightly sealed, have an auto mechanic look at the compressor.
Refrigerant is that magic fluid that turns warm air into cooler air, keeping the interior environment crisp and chilly. Often, the coolant may leak out of the compressor due to sudden impact or worn-out refrigerator pipes.
With no refrigerant to work with, the air conditioner lets warm air pass in and out of the pipelines, thus, raising the cabin temperature. The movement of warm air inside the compressor pipes also produces a buzzing noise that feels way more irritating than the warm thrusts of air. Start by mending the leaks before adding new refrigerant to the lines.
Loose and Dirty Air Filters
Before the warm air interacts with the refrigerant lines in the compressor, it passes through air filters that clean the air of any dust and debris. The filters are fastened with bolts and screws, which become loose and shaky with time. As air passes through the wobbly and clogged-up air filters, it emits a loud rattling noise. Tightly secure the air filter back onto the compressor but make sure to unclog the surface before you mount them back.
Broken Compressor Clutch
The clutch works as a pulley that engages and disengages the AC compressor on demand. If broken or damaged, the compressor clutch fails to operate the air conditioning system when required. In other words, the compressor won’t be able to access engine power making it physically impossible for AC to function. In such cases, instead of replacing the entire compressor unit, simply replacing the clutch would do the job.
Instead of relying directly on engine power or engine battery, automotive air conditioners depend on capacitors to operate. A capacitor works as the powerhouse for AC by supplying electric current while the engine is shut down.
If the capacitor battery is drained out, it fails to supply sufficient power to the AC resulting in a noticeable hum. Also, in the case of a loose or faulty capacitor, the compressor fan doesn’t turn on and instead produces a squealing noise due to friction.
Be it the compressor itself or the wiring surrounding it, automotive air conditioning systems get faulty and run down all the time. Unless you make regular car maintenance visits to the workshop, the wiring could get damaged beyond repair. Even if your AC unit works perfectly, being connected to faulty wires increases the chances of burnout. Worst case scenario, the worn-out wires can even lead to electrical fires that jeopardize your life.
Noisy Car AC Compressor – Treating 6 Unusual Sounds From Your Car AC
While faulty compressor sounds are unusually loud to neglect, they don’t always indicate the same problem. If you pay closer attention, you can easily distinguish between the type of noise the compressor makes and what it unfolds. Let’s discuss the most alarming noises you might hear from your car AC compressor, what they indicate, and how you can treat them.
It is pretty common for AC compressors to make consistent vibration sounds. Most of the time, it simply indicates the need for lubrication. Since the compressor’s components are adequately lubricated by default, sudden dryness points out a leakage or low pressure in the compressor. Either way, follow the steps to eliminate car AC compressor vibration noise.
For effective lubing, source a quality refrigerant oil, particularly the TSI supercool AC compressor PAG. Make sure to purchase the Wisepick AC oil injector as well for hassle-free application. Start the car’s engine and put the AC on maximum performance before injecting the oil into the cooling system.
Although most loud noises from your car’s AC compressor would mean a trip to an auto garage, squealing noise is not one of those. A loud shrieking noise from your car’s bonnet normally indicates a faulty serpentine belt. Here are a few ways you can make the whining noise go away:
- Sprinkle your standard tap water on the serpentine belt to slick it down with the noise.
- If the shrieking continues, check the condition of the belt. If it shows signs of weariness, look for a replacement – the Goodyear belt might serve the need.
Knocking or Grinding Noise
The repulsive sounds of knocking and grinding from your car’s hood are often correlated with a wobbly compressor part. In other words, your car’s AC compressor isn’t correctly installed, or the attaching bolts and nuts have gone loose. Start the engine and repeat the following procedure to address the car AC compressor grinding noise:
- Open the car hood to have a clear view of the compressor and AC system.
- Try exerting force or shaking the compressor to see if it wobbles or not. If it appears shaky to the touch, you need to tighten the bolts securing the component.
A loud buzzing sound from an automotive AC compressor indicates damage to the refrigerant lines, possibly a leak. Not just that, you may hear a similar humming noise if the cooling system is overstuffed with the refrigerant, typically known as Freon.
Injecting refrigerant beyond a certain threshold not only affects the performance of the AC but also damages the mechanical parts of the fixture. If not tackled sooner, you might end up replacing the entire unit.
If you spot a leak in the cooling system, get your hands on a Freon leak repair kit. Use a leak detector to pinpoint the exact location of the fissure and apply a refrigerant leak sealer to mend the crack.
The hissing noise isn’t generally correlated with compressor malfunction. The sound indicates the spontaneous flow of refrigerant inside the cooling system and remains evident even after the engine is switched off.
Be that as it may, you cannot neglect possible malfunctions associated with the noise. Sometimes, it also signals a leak in the refrigerant line, internal valve, or extreme pent-up pressure inside the compressor. Instead of handling it yourself, hiring a professional to look into it is better.
While it seems trivial to most, a consistent rattling noise is a warning noise that signals something terrible is about to go down with the car AC compressor. From a worn-out serpentine belt to a damaged compressor clutch, multiple factors could contribute to a rattling noise. Unless it’s something as casual as injecting lubrication into the cooling system, prefer leaving it to a professional mechanic to handle.
People Also Asked
Here are the answers to some questions commonly asked by people:
Why does my car’s AC compressor produce a whining noise when accelerating?
Whining noise is typically produced as a result of friction between the serpentine belt and the compressor hoses. Spray some water on the belt to overcome the friction but if the noise doesn’t go away, try changing the serpentine belt.
Is it normal for a car AC compressor to make rattling sounds?
Yes, it is normal for a car AC compressor to make rattling sounds, as it indicates the normal functioning of the air conditioning system. But if you hear it consistently, it may hint at a possible hidden fault. Make sure to have it checked with an auto mechanic.
How much does a new car AC compressor cost?
Replacing the car AC compressor will normally cost around $1,100. But if you go the do-it-yourself way, you can cut the costs to $850 – $900.