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Why Is My AC Making Noises?

We know it’s worrying to hear odd noises coming from your AC, especially if you live in Arizona where properly working ACs are vital.

Noises are typically an indicator that there is an issue with your AC that needs fixing.

To diagnose the issue, you’ll need to know what kind of noise your AC is making, such as:

  • Hissing/bubbling
  • Gurgling
  • Clicking
  • Slamming

While it’s difficult to troubleshoot the exact reason behind the noise without inspecting your AC, we can provide some general information about why you’re hearing these noises.

Rather have an HVAC professional take a look at your AC to see what the problem is?

Contact Advantage Air Mechanical. We perform same-day repairs on all AC brands.

Noise #1: Hissing/bubbling

If you hear hissing/bubbling noises coming from your outdoor AC unit, it’s usually a sign that you have a refrigerant leak. The hissing noise you’re hearing is likely the sound of refrigerant squeezing out of a small hole or leak.

Refrigerant is a substance that absorbs the heat from your home's air and dumps that heat outside. If you have a refrigerant leak, your AC cannot absorb as much heat and therefore cannot cool your home as effectively.

Some other signs that you have a refrigerant leak include:

  • Ice on your indoor and outdoor units
  • Your AC blow hot air during the daytime and cold air at nighttime

You’ll want to contact a professional if you suspect you have a refrigerant leak to seal the leak and refill your refrigerant.

Noise #2: Gurgling

Gurgling noises coming from your AC can typically be attributed to two things:

1. A refrigerant leak: In addition to bubbling noises, refrigerant leaks can also cause a gurgling noise. Air enters the leak and causes a gurgling noise as refrigerant travels through the refrigerant lines.

Again, you’ll want to contact a professional regarding a refrigerant line leak to repair it.

2. A clogged condensate drain line: On top of absorbing heat, your AC system absorbs moisture from the air in your home. The refrigerant dumps the heat outside; meanwhile, the condensate drain line in your AC system is used to dump the moisture outside.

Over time, the drain line can get clogged with dirt, debris or mold. If the drain line is clogged, the water can’t easily exit the drain line, creating a gurgling noise. If the clog isn't too bad, you may be able to clean it on your own.

clogged condensate line visual

However, if the clog is high-up in your line, removing it yourself might damage your AC system. If that's the case, you’ll want to reach out to a professional to unclog it.

Noise #3: Clicking

If you hear a clicking noise and your AC doesn’t turn on, you most likely have one of the following problems:

1. A malfunctioning thermostat: You probably hear your thermostat make a clicking noise when you adjust its settings. This is because a part called the “relay” opens and closes to turn on/off your AC.

If you hear constant clicking near your thermostat, it has either a broken relay or worn out wires.

2. A glitchy control board: The control board receives commands from the thermostat and then tells parts of the AC to turn on or off.

If the control board is glitchy, a relay part could time out and fail, causing an unusual clicking noise.

3. A bad capacitor: Some older ACs have a capacitor in their outdoor unit that acts as a giant battery. The capacitor gives your AC the extra juice it needs to start up.

If you hear a clicking noise followed by a humming sound near your outdoor unit, you probably have a bad capacitor. Your outdoor unit is trying to turn on without the help of the capacitor and failing.

If you have any of the above problems, contact a professional to avoid damaging delicate parts of your AC.

Noise #4: Slamming

If you hear slamming noises from your AC, pay attention to where they’re coming from.

If you hear a slamming noise coming from inside your home, your blower fan might be loose. The blower fan is used to pull in warm air which is cooled by your AC and sent back into your home.

With time, the mounts on the fan can loosen. After the mounts loosen, any time the AC stops and the fan slows down, the wheel of the blower can bang against its metal casing.

To fix a loose blower fan, an HVAC technician can inspect the blower wheel and tighten any loose components.

If you hear a slamming noise coming from outside your home, the compressor springs in your outdoor unit might be broken.

The compressor springs hold up refrigerant pumps in your outdoor unit. Without the springs, your compressor cannot circulate refrigerant throughout your system.

Over time, the compressor springs can break. The loose refrigerant pump then slams against the compressor’s casing.

Unfortunately, compressor springs are nearly impossible to fix, so if this is your issue, you might have to replace the entire compressor. An HVAC technician will be able to diagnose whether or not a repair is possible or if you will have to replace the compressor.

Ready to get your AC back to normal? Contact Advantage Air Mechanical

We make the AC repair process as convenient as possible with 2-hour appointment slots and same-day repair service.

On top of that, we offer coupons and financing options to make your repair as affordable as possible.