Why Is My Air Conditioner Making Gurgling Noise?

Do you hear the sound of running water from your air conditioner? You're probably wondering why your AC is making gurgling noises. What does this mean? We gathered information about this to give you the answer.

This type of noise coming from your HVAC system most likely signals these problems: 

  • Issues with the refrigerant line
  • Clogged drain line
  • Condensate pump failure

Keep reading as we delve into why these problems make your air conditioner produce a gurgling noise. We'll also discuss what problems other noises from your AC indicate and other related issues you might encounter with your unit.

An air conditioner filter cleaning, repair and check, Why Is My Air Conditioner Making Gurgling Noise?

Why Does A Refrigerant Line Problem Causes A Gurgling Sound?

The gurgling sound from your AC may be caused by air trapped in the liquid coolant lines, which shouldn't happen if the lines are properly sealed.

Air condition unit refrigerant fluid leaking

A refrigerant leak might result in low pressure in your unit. On the other hand, a refrigerant overcharge can result in too much pressure, leading to pressure imbalance inside the unit.

If your system is creating a gurgling noise, it's usually safe to keep it running. However, you should contact a professional specialist to inspect the situation and determine the source of the problem.

What Causes Drain Line Clogs In Air Conditioner Units?

Condensation drain has become plugged and must be cleaned

The evaporator coil of your domestic air conditioner is where the cold refrigerant is stored. Condensate forms when warm air from your home comes into contact with the cold refrigerant via the coil.

Condensate then collects at the base of your evaporator coil, which is drained outside through the condensate drain line.

Debris, dirt, and mold build up in your drain line over time and cause it to clog. Condensate backs up the line due to the obstruction, resulting in gurgling sounds.

How To Unclog AC Drain Line?

For this task, you'll need a wet/dry vacuum. To start, locate the condensate drain line's end. This is a white PVC pipe attached to your outside wall.

Next, connect the vacuum hose to the drain line and start the vacuum for two minutes. Then, inspect the vacuum to see whether the blockage has been removed.

You've probably cleared the blockage if there's a lot of brown-colored water and debris in the drain.

However, if there are still gurgling sounds after you have vacuumed the drain line, you need to call an HVAC professional to help you fix the problem.

What Happens When The Condensate Pump Gets Damaged?

The job of the condensate pump is to transport water from the drain pan to the condensate line, where it is discharged from your home. If it gets damaged, it might produce bubbling or gurgling sounds caused by excess moisture in the pump.

How Loud Should An Air Conditioner Be?

The loudness of air conditioners is determined by their age, kind, and current condition. Expect older machines to be noisier in general.

As older units wear out, the decibel levels may rise, but modern air conditioners are constructed with noise reduction in mind.

The decibel level of an air conditioner varies greatly from one unit to the next. A modern air conditioner using noise reduction technology may only produce 25 dB of noise, which is barely audible.

Comparatively, portable air conditioners may reach a decibel level of 55.

Manufacturers assign a decibel rating to air conditioners, which is listed on the label. Air conditioners with a strong cooling output frequently have a high decibel output.

Some air conditioners with sound-reduction technology are also more expensive than standard air conditioners. The apparent loudness will be reduced by sound insulation and distance.

What Are Common AC Sounds And What Do They Indicate?

Now, let's get to know what are the common sounds your air conditioner makes and why they should not be ignored:

1. Rattling/Banging Noise

While this is not always the case, it's extremely likely that an AC noise that sounds like forceful hammering is caused by a condenser problem. Here are several reasons for the alarming sounds as well as possible solutions to fix them:


  • Dirt particles infiltrated in your condenser unit.
  • As a result of loosened screws.
  • Compressor or fan motor failure.


  • To get rid of the stuck objects, remove the condenser cover and clean it.
  • Use a screwdriver to tighten the loose screws.
  • For compressor or fan motor failure, an HVAC professional will be able to pinpoint the exact problem and recommend whether you should repair or replace the unit.

2. Squealing and Screeching Noise

The squealing and screeching sound your AC makes could be attributed to several factors:

  • Fan motor bearings that are faulty
  • Belt is worn out or broken
  • There is high pressure in the compressor unit

Remember, if your air conditioner makes a high-pitched screeching noise, it implies that significant pressure has built up in your compressor. Turn off the air conditioner right away because high pressure can create an explosion.

These problems are best handled by an HVAC professional.

3. Pulsating Noise

There may be nothing to be concerned about if your AC makes slow pulsating noises. If the noise is loud and repetitive, though, it indicates cause for concern. These could be because:

  • The coil or fan blade is loose
  • The plastic base of your AC is pulsating
  • There is contact between refrigerant lines and AC walls

Here are some possible solutions you can try when your AC makes this kind of noise:

  • Tighten coil or fan blade screws.
  • Consider changing the plastic cushion with a hardwood one to reduce vibrations. You can also fasten the unit tightly to the pad and support it with little rubber blocks.
  • Move the refrigerant lines slightly away from the wall and add rubber or foam insulation.

4. Hissing Noise

The following are some of the potential reasons why your AC is making hissing noises:

  • Refrigerant or compressor valve leak
  • High pressure in the compressor

The only solution to resolve these issues is to contact an HVAC professional immediately.

Repair mechanic using measuring equipment checking maintenance outdoor air compressor unit

5. Clicking Noise

A clicking sound at the beginning and end of a cooling cycle is perfectly normal. But a clicking sound that does not go away is alarming. Let's have a look at some of the possible causes:

  • Your AC fans are obstructed
  • Loss of charge in a capacitor
  • Electrical signals error
  • Your AC fan isn't working properly
  • Thermostat won't work

6. Whistling Noise

This noise may not be as loud as the others, but it does indicate that something is wrong with your air conditioner. Here are some possible explanations:

  • There's a leak in the AC duct.
  • There is an obstruction in the AC airflow.

Air conditioner with dirty filter

To fix this, make sure that your AC ducts are properly sealed. In addition, regularly check and clean your air filters because they are the primary cause of AC airflow obstruction.

7. Humming Noise

It's not unusual for an AC motor to emit faint humming sounds, but when they get loud, it's cause for alarm. It's possible that your air conditioner is humming if:

  • Insufficient lubrication level
  • Failure of the contactor
  • Coils with a bent fin

8. Cracking Noise

The coils in your HVAC unit's evaporator can freeze if the temperature is set too low and the moisture is not draining properly or the fins are dusty. The shattering sound of ice falling from these coils reverberates throughout your system.

Disassemble your air conditioner to gain access to the fins and diagnose it. Use dish soap to properly clean the fins, which should then be allowed to dry. Only disassemble the air conditioner if you've done it successfully previously; otherwise, hire a specialist.

9. Buzzing Noise

When you hear this sound, it can indicate one of these things:

  • Compressor failure
  • Loose parts in your AC
  • Capacitor or contactor failure
  • Motor malfunction
  • Loose wirings
  • Frozen AC parts

Consult an HVAC specialist to determine which of these issues you are experiencing.

10. Grinding Noise

A compressor or motor problem could be the cause of a grinding noise emanating from your air conditioner.

A grinding sound coming from the outside unit indicates a problem with the compressor. When a compressor's pistons are running, they make a loud grinding noise.

Rather than repairing the internal sections of the compressor, it is generally advised that the entire compressor be replaced.

11. Dripping Noise

Water leaking from the air conditioner drips from the cooler

An air conditioner that drips can be a source of concern. It could be due to a buildup of moisture in the drip pan, which is normal. However, if the dripping sound is caused by excessive moisture, it may be cause for concern.

Here are a few possible reasons as to why your AC makes this sound:

  • Condensation at a high level.
  • Freezing AC coils.

In Closing

When your air conditioner behaves strangely, such as producing noise or emitting a foul odor, it's trying to alert you to an issue that needs to be addressed.

Regular professional inspections and good maintenance of your air conditioner can help avoid unusual sounds from emerging from your air conditioner.

If you're experiencing any issues with your appliance, it's best to figure out what's causing it as quickly as possible. You can avoid costly repairs down the road by resolving problems as soon as possible.

Check these related articles if you have issues with noise from your HVAC system:

How To Reduce Noise From A Central Air Conditioner

Heat Pump Sounds Like Helicopter – What Could Be Wrong?

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