The dashboard of a Landrover removed to reach the blower motor.

Noises from the air conditioning system

In Automotive Diagnostics by HomeTowne Auto Repair & Tire

Whenever something is wrong with your vehicle, you may begin to hear strange sounds. The a/c is no different. Noises from the air conditioning system are one symptom you may notice when there is an issue.

What does a normal AC sound like?

When the ac compressor comes on, depending on the type of vehicle, you may hear a click and you might see the tachometer go down a little bit and back up as the engine is compensating for the load of the ac compressor. 

Weird noises from the air conditioning system

Now that we’ve covered what you should be hearing, let’s move on to those odd noises, and what’s causing them. 

Strange air conditioning sounds include:

  • Buzzing noises: If you notice a buzzing noise, it could be an ac compressor relay.
  • Clicking sounds: You should also keep an ear out for clicking sounds. A loud clicking is one indicator that the a/c compressor clutch is going bad. If it’s happening quickly, it could be that the system is low on Freon.
  • Clicking sounds inside the car: This noise may be due to actuators behind the dash that control the vent doors. Sometimes, the plastic pieces break or the motors go bad, and they will make a clicking noises.
  • Squealing noise: Squealing sounds are sometimes created if the a/c compressor clutch wears out. Other potential culprits include a bad pulley or pulley bearing, oil getting onto the clutch, or the compressor seizing up. The squealing could also be a loose a/c compressor belt.
  • Rattling sounds: The ac compressor or the compressor clutch going bad produce rattling sounds, at times. This noise – as well as knocking sounds and groaning noises – can also be heard if mounts are loose or broken. The drive belts becoming worn or damaged is another possibility. 
  • Rattling noise inside the vehicle: If you hear a rattling noise from within the car and you have kids or you put stuff up on the dashboard, we have found that paper clips and pens will fall down in the vents. Depending on how high you have the blower motor up, they might rattle around in there.  
  • Vibrating noises: An a/c hose rubbing against a component could lead to vibrating sounds. The blower motor going bad electrically or being unbalanced can create a vibration noise inside the car.
  • Swooshing sounds: As the ac system starts to build pressure, you may hear what sounds like water going through pipes or a swooshing noise. It usually has to do with the expansion valve or the orifice tube that the Freon is expanding through.

Other a/c problems

A leaking air conditioning condenser.
Leaking air conditioning condenser.

In addition to hearing noises from the air conditioning system, drivers may notice that it just isn’t working correctly. Maybe hot air is blowing out of the vents when the AC is turned on, or no air is coming out at all.

Air conditioning problems can be the result of several issues. A constricted air conditioning condenser and being low on freon are among the possible reasons why the a/c isn’t working.

Our Woodbridge mechanics can perform car ac repair services. This includes a/c diagnostics and electrical diagnostics, replacing parts, and tracking down any leaks. Check out this article we wrote to learn more about the a/c repair services we offer and what you can do to maintain this system. Conducting noise diagnostics is another service we offer.

An air conditioning condenser fan.
Air conditioning condenser fan.

If you are hearing any noises that are listed above or others that we didn’t mention – whether they are coming from the air conditioning or not – reach out to us. We can help you determine the problem.

HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.