Car Making Noise When Ac Is On – Common causes and solutions

Have you ever experienced a car making noise when AC is on? If your car air conditioning is making clicking noises when it’s turned on, it can be an indication of a faulty air conditioning system.

This can cause extreme anxiety, particularly on hot summer days. The clicking noise when the AC is on in your car could be caused by various reasons such as a faulty compressor, hose, component mounts, or clutch. It is important to identify the specific noise type and source of the problem. In case your car air conditioner is making clicking noise when turned off, it could also be a sign of a problem with the system. Ideally, a well-maintained AC wouldn’t make loud or strange noises.

What’s Up With That Noise From Your Car’s Air Conditioner?


Many people don’t realize that a serpentine belt operates their car’s air conditioner. The components of an engine receive their power from the crankshaft through a long rubber belt called a serpentine belt. This belt is comprised of the alternator, tensioner, water pump, power steering pump, crankshaft pulley, idler pulley, and air conditioner compressor. Any and all functionality, including the air conditioner, may be jeopardized if this belt fails. You risk having your battery die and your engine overheat.

Because of this, replacing your serpentine belt at the recommended intervals is essential. In doing so, you can avoid a lot of unnecessary expenditures, headaches, and inconveniences. Now that you know the basics about this crucial belt, we can get to the bottom of why your car’s air conditioner is making so much noises.

Common types of noises when AC is on

Not Required Immediate Attention (Means you don’t have to fix or call professional on the spot)

Squeaking or Clicking AC

When you switch it on, does it click? A soft clicking noise may be typical. However, if it happens quickly and loudly, the clutch may be worn. If clicking occurs frequently, the blower motor may be being hampered by extraneous objects.

If this is the case, a short YouTube search will show you exactly how to inspect your blower motor. Your air conditioner may be squealing in extreme circumstances. This can be a sign that the clutch is nearing the end of its useful life. It might also imply that the pulley is broken or polluted with oil.

Rumbling Noises

When you turn on your air conditioning, do you hear a vibrating sound coming from the cabin? This could indicate that the hose is rubbing against anything in the engine area, such as another hose or another object. If you look underneath the hood and notice any rubbing or scratching, you can reroute the hoses using cable ties.

Whistling and hissing

(This was certainly relevant when the air conditioner make noise when it turned off.)

Don’t worry about whistling and hissing, which aren’t anything to worry about. It’s a sound that might happen after you turn off the air conditioner. As the refrigerant moves through a metering component, areas with high pressure and areas with low pressure even out. When you turn off your car, basically, nitrogen moves from one side of the compressor to the other.

Required Immediate Attention (Means you have to fix or call professional as soon as possible)

Noises That Rattle And Knock

Noises like rattling or knocking can come and go. This could mean that the mounts are loose or broken. In this case, the mounts and bolts may need to be changed or tightened. They could also be coming from somewhere inside the compressor.

2nd Scenario

If the noise gets louder when you hit the gas, it could mean the compressor needs to be replaced. It may be important to check on the health of your drive belts. Rattling and knocking sounds could also come from the clutch, the pulley bearings, or the blower motor.


(This is a sign of compressor falling or damaged and it directly relate to when the AC turned on)

AC unit buzzing every few minutes. This could be a sign that too much refrigerant has been put into the system. This could mean that the refrigerant is getting into the intake port of your compressor. If refrigerant gets into your compressor’s intake port, it can cause the cooling to be bad and damage parts. This is a problem that needs to be fixed as soon as possible, because if it isn’t, you may have to replace the compressor entirely.

Are you still confused how can I diagnosed the issue of making ac noises when it’s turned on?

Don’t Panic!

These are the specific issues directly relate to it other than buzzing.

Drive Belt is Loose or Broken

Car Making Noise When Ac Is On

(This problem is already explained above under sub heading Rumbling noise)

The compressor is driven by a drive belt. It can generate a noise when the compressor is turned on if it is loose or damaged. Because it is constructed of rubber, the drive belt might degrade over time and cause issues.

Clutch Failure Due to Damage

Car Making Noise When Ac Is On

(This problem is already explained above under sub heading Squeaking or Clicking AC)

When the air conditioner is turned on, the compressor is activated by a clutch. When the compressor is turned on, it may make a noise if it is damaged or failing. Wear and strain, damage, or a defect in the clutch itself are only some of the potential causes of clutch failure.

Filter Blockage

The air conditioner may create a noise if the The filter, which keeps out debris and grime from the air conditioner, can become clogged over time. As the air conditioner struggles to push air through the blocked filter, you may hear a humming or squealing sound.

Fix Ac Car Making Clicking Noise

Your car air conditioner’s noise when it’s turned on is a problem you can solve in a few ways.

  • The drive belt must be replaced if it is loose, broken, or missing. Every car parts store should stock replacement belts.
  • If the compressor clutch is not engaging, have it checked out by an expert.
  • Something stuck in the ventilator’s blower should be freed. You can do this on your own by removing the fan and checking it thoroughly for any debris.
  • Filters that become blocked can be easily replaced. Replaceable filters can be purchased at any auto parts retailer.
  • Repairing or replacing a broken or failed compressor is a job for experts.

Frequently Asked Questions:

Why Does The Evaporator In My Car’s Air Conditioner Get So Dirty?

Cooling the air that enters your car’s interior is the job of the evaporator, which is housed in your dashboard. The evaporator’s efficiency can degrade over time if it gets dirty.

The evaporator may have to be changed if it becomes so soiled that it can no longer function properly. You should probably get a pro to handle this for you.

What kind of noise should I expect from my car when the AC is on?

The noise you hear can range from a rattling or clicking sound to a screeching or grinding noise, depending on the underlying issue.

Is it safe to drive my car if it’s making noise when the AC is on?

Having your car evaluated by a mechanic can help you figure out what’s causing any strange noises when the air conditioning is on, as well as whether or not it’s safe to continue driving.

Can I fix the noise myself?

Problems like a clogged cabin air filter or a slack belt are easy fixes for the do-it-yourself. Other problems, however, such as a broken compressor or motor, call for the use of specialized equipment and knowledge.

How much does it cost to fix a car that’s making noise when the AC is on?

The cost of repairs will depend on the underlying cause of the noise. A minor issue, such as a dirty filter, can cost as little as $20 to fix, while a major issue, such as a damaged compressor, can cost upwards of $1,000 to repair.

Car Makes Humming Noise When AC Is On



If the A/C blower motor in the dashboard is making the humming noise, then dust buildup or an imbalance from something being sucked into the blower could be to blame. A qualified mechanic or expert should investigate the blower motor to find out what’s causing the noise and how to fix it. If the blower is dirty or broken, it may need to be repaired or replaced.

Car Air Conditioner Noise When Idling

Buzzing or Whirling sound: It’s common for the AC compressor to make a buzzing noise when it’s running at idle. The engine’s motor and fan are making the noise.

Rattle Sound: The AC compressor pulley or the belt tensioner may be the source of the rattle. The tensioner is usually the issue, however rattles and vibrations might also be caused by a weak spring.

About The Author

Avatar for Ibrar Ayyub

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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