Why my AC is Making Noise (& How to Fix It)

ac unit, outdoor unit, air conditioning units, hissing noise, air conditioner making noise, fan motor

If you are wondering why your air conditioner is making weird noises and how you can resolve the issue, you are at the right place.

We are your AC experts, and in this guide, we will cover all types of air conditioner noises, their causes, and their solutions. Besides that, we will also share some amazing troubleshooting hacks and tricks to help you take proper care of your air conditioner and improve its performance and lifespan.

So here we go.

Types of AC Noises and Their Solutions

ac unit, outdoor ac unit, air conditioner making, fan motor, banging noise

1. Banging or Rattling Noise From AC

The first extremely common sound that you might have heard in your noisy air conditioner is a loud, aggressive banging sound. This kind of sound might or might not be a result of a faulty condenser, and here are some methods to fix this noise:

  1. Cleaning Dirt Particles Stuck in Your CondenserWhenever you come across that loud rattling noise in your AC, start the troubleshooting by cleaning the condenser. Sometimes, small particles such as leaves, sticks, or dirt get stuck in the condenser and cause an annoying sound. So remove the condenser cover of the outdoor AC unit, remove the stuck particles, and the noise will be gone. If you find it tricky or risky, call a professional.
  2. Loose Screws –Rattling noise can also result from loose screws in an air conditioning unit. When an AC system works, both its inside and outside units vibrate. Over time, this can result in the loosening of screws and develop an unwanted noise. To fix this issue, simply tighten the screws using a screwdriver.
  3. Broken Fan Motor or Compressor –If your ac system is making a banging noise while starting, it can be due to a broken compressor or an imbalanced motor. In this case, you would have to replace your fan motor or condenser, which can be pretty costly. Therefore, we suggest that if your air conditioning unit has crossed the decade mark, you should replace it instead of wasting money on a motor or condenser. However, if the system is under warranty, you can consult your HVAC unit specialist to learn the exact reason for the noise.

2.  Screeching & Squealing AC Noises

ac unit, air conditioning system, refrigerant leak, fan blades, clicking noise, air conditioner makes

If you are detecting a high-pitched, screeching sound in your AC, it can be due to two main reasons.

  1. Faulty fan motor bearing-If your AC’s motor bearings are broken, they will need an immediate replacement.
  2. Worn out or broken beltDucted or central air conditioners often make such noise because their belts wear out over time. Also, high humidity levels can cause the belt to contract and expand in summers and produce unpleasant noise. In such cases, it is recommended to contact a qualified HVAC unit professional to repair or replace the belt.
  3. High Pressure in Compressor UnitHigh pitch loud noise can also be due to high pressure in your air conditioner. If unnoticed, it can also lead to an explosion. So, if this is the case with your AC, turn it off instantly and contact an AC unit professional as soon as possible.

3. Pulsating Noise

fan blades, clicking noise, hvac system, loud buzzing noises, air filter, high internal pressure

If your air conditioning system is producing slow pulsating noises, you don’t have to worry much. Unless the noise is loud and rhythmic, some simple measures can stop this disturbance. Here are some reasons for this kind of noise:

  1. Loose Fan Blade or CoilA loosened fan blade or coil can cause this type of noise. And to resolve this issue, all you have to do is tighten the screws with a screwdriver.
  2. AC Plastic Base Pulsating –  If your AC’s outdoor unit plastic base is pulsating, it can be due to the compression motion. In this matter, replace the plastic pads with wooden ones, and the vibrations will be minimized. Likewise, you can clamp the unit down on the pad and support it on small rubber blocks. This will reduce all the unwanted vibrations and eliminate the unusual noise.
  3. Refrigerant Lines Getting in Contact With the AC WallsIf your air conditioner’s refrigerant lines are touching the wall, move them away, add some insulation such as rubber or foam material, and there will be no noise.

4. Hissing Sound

hvac system, ac noise, cooling cycle, outside unit, ac clicking noise, squealing noise

If you wake up in your sleep fearing a snake and hear some hissing noise, it might be due to your faulty air conditioner. Here are some explanations for this kind of noise:

  1. Leaking Refrigerant: Any damage to the refrigerant line can generate a refrigerant leak in your AC.Usually, the refrigerant lines get damaged over time and start causing leakage. In these cases, you would have to contact a professional to get rid of the leaking problem as, unfortunately, there is no DIY solution for it.
  2. Compressor Valve LeakCompressor valves control the pressure of the refrigerant, and any fault in these valves or some leak can result in a hissing noise. If you face this issue, we suggest you contact an HVAC unit specialist.
  3. High Compressor PressureThe extra pressure in the compressor can lead to a shrieking noise. If you feel such an issue, just shut down the system and call a specialist.

5. Clicking Sounds

outside unit, squealing noise, screeching noise, indoor blower motors, clanking noise

A minor clicking sound during the AC’s start or turn off is absolutely fine. However, if the clicking sound is constant, there can be several reasons behind it, which may lead to major issues in the future. Here are some of them:

  1. Obstruction in AC Fans If there is some obstruction in the air conditioner fans, just perform your simple routine maintenance— lift the outdoor unit’s cover, and wipe your fans.
  2. Lost charge in the capacitor if the AC’s capacitor has lost charge, then it won’t be able to power the compressor. However, the outdoor unit will unsuccessfully try to turn on the AC, and you will hear a continuous clicking sound. If you notice such a problem, contact a professional.
  3. Fault in Electrical Signals Defective electrical signals can cause the AC switch to turn on and off and create some strange noises. If you witness some sparks along with the noise, call an HVAC technician.
  4. Loose AC Fan –The air conditioner fan can become loose over time, mainly due to continuously hitting the outdoor unit’s case. In this problem, just call the HVAC service and get the fan tightened or replaced.
  5. Malfunctioning thermostat faulty or broken thermostat will not let your AC turn on and produce a loud clicking sound. If the relay is broken or there is some wiring issue in the system, you have to contact a professional for repair.

6. Whistling Sound

screeching noise, outdoor fan motors, ac making noise, modern hvac units, copper lines, air conditioner turns

If your air conditioner is making a pesky whistling sound, then here are some of the possible reasons behind it:

  1. A Leak in AC DuctA leaking air conditioner duct can produce a sound like someone is whistling. One simple and speedy solution to this problem is sealing the duct tape properly. It is important to fix this problem as a leaky duct can cause energy loss and increase your bills.
  2. Obstruction in AC Air Flow –  An obstruction or block in airflow in the air conditioner can lead to higher pressure in the blower motor and irritating whistling sounds. One typical reason for a block in the system is dirty air filters. So, if you are noticing such an issue in your AC, just clean the dirty air filter and repeat it from time to time. It will terminate the current noise and prevent such problems in the future.

7. Humming Noise

screeching noise, strange noises, bubbling noise, fan belt, loose or broken part, failing thermostat, rattling sound

Here are some of the reasons and solutions for a humming noise in your AC.

  1. Low Lubrication LevelsAC’s motor needs timely lubrication for proper functioning. If you skip doing so, it will produce a humming sound that will eventually become a loud grinding noise. To solve the problem, just lubricate the motor and if the problem persists, make a call to an HVAC technician.
  2. Contactor FailureAC’s contractor is primarily responsible for controlling the current flow in the system. If the air conditioner is turned off, the contactor disables the power supply. However, a failure in the contactor will make the AC get power but won’t turn it on, resulting in a humming or strong buzzing sound.
  3. Damaged Fin CoilsIf the AC’s fin coils get bent, they can also produce some humming noise in the unit. To solve this issue, all you have to do is use a metal comb and straighten the bent coils.

8. Cracking Sounds

If the temperature of your air conditioner is set too low and the moisture is somehow not able to drain properly, or the fins are dirty, then your AC’s evaporator can freeze. It can cause ice formation in the system and eventually lead to the melting of ice and the production of echoing cracking sounds in the air conditioning unit. The AC drain is a small tube that runs from the air conditioning system in a vehicle to the outside of the vehicle.

To fix this issue, just disassemble your AC, get access to its fins, wash them thoroughly with dish soap and let them dry. Then, assemble the AC back, and it will be fixed.

9. Buzzing Noise

air conditioner starts, ac making, unusual sounds, copper lines connected, electrical issues, sound dampening technology

Buzzing noise can be an outcome of several issues. Here we have given some most prominent causes of such noise with their right solutions:

  1. Compressor Malfunctioning or Loose Parts The most common reason for that buzz in your air conditioner is either a faulty compressor or loose parts in the system. To sort out these issues, you can replace the compressor or tighten the loose parts or other electrical components.
  2. Capacitor BreakdownIf the AC’s capacitor has gone bad, it will refuse the fan from turning on, and there will be a loud buzzing sound due to extra friction. However, a replacement or repair of the capacitor can solve the issue.
  3. Damaged MotorA faulty motor in the cooling system can also be the reason for the buzzing noise in your AC. To keep the motor safe, you should keep the copper lines well insulated and minimize the metal-on-metal contact.
  4. Loose WiringIf there is a constant buzzing noise in the AC, it is probably because of loose or exposed wires. To fix the issue, immediately turn off the AC as it can lead to an electric spark and fix the wirings.
  5. Freezing of AC partsThermostat set too low— low refrigerant can lead to freezing of the indoor units of the air conditioner and result in a buzzing sound. To get rid of these unusual noises, you would have to consult an HVAC technician.

10. Bubbling & Gurgling AC Noise

Here are the main reasons behind bubbling and gurgling noises in air conditioners:

  1. Improper Sealing of Refrigerant LinesProblems such as a refrigerant leak can often lead to a striking gurgling noise in the AC. A simple solution to sort these issues is to seal the lines properly.
  2. Excess Moisture in Your ACA blockage in the condensate drain line or crack in the condensate pump can lead to a high moisture level in the AC and create a bubbling or gurgling sound. You can solve the issue by disassembling the AC and inspecting the drainage line. If the line needs a complete replacement, you should hire professional help.

Why Should You Never Ignore AC Noises?

electrical issues, cooling unit, entire system

AC noises are not some simple issues you can avoid unless the AC becomes completely dysfunctional. On the contrary, any noise or smell in the AC signals a problem and requires your immediate attention. If you avoid such AC noises, you might be turning minor issues into bigger ones and inviting more damage or repairing costs to your AC. Also, if these matters go unnoticed, they can permanently damage the AC or reduce its overall lifespan.

Furthermore, loud noises in the AC can also be a hazard. For example, refrigerant leaks and high-pitched squealing noise can even lead to refrigerant poisoning and hurt your loved ones. So, it is highly advised that the sooner your resolve these issues, the better. Immediate action will reduce the future maintenance and repair costs of the AC, improve its functioning and increase its overall life.

Therefore, we recommend that you take proper care of your air conditioner and have timely maintenance and inspection performed by us at Las Vegas AC Repair. If you have any questions, let us know by contacting us today.

Picture of LasVegas AC Repair

LasVegas AC Repair

With over thirty years of experience, we’ve been giving air conditioning, heating, pipes, as well as interior air quality solutions to the Las Vegas Valley. As a locally operated family company, we proudly serve our customers with stability and professionalism, and trust. We want you to end up being as well as stay part of our family.

© Las Vegas AC Repair All Rights Reserved.