Skip the auto shop - Our mechanics make house calls

Q: When I turn the AC on, it makes like a rattling noise under the hood. As I keep the AC on, the sound gets louder.

asked by on

Rattling noise when I turn AC on and it increases if I continue to leave the AIR on

My car has 41000 miles.
My car has an automatic transmission.

Your car’s air conditioning system is driven by an air conditioning compressor that has a small clutch on compressor pulley. When this becomes worn out or not properly lubricated enough, this can cause it to fail which can make a very loud rattling noise as you describe. To avoid any unnecessary repairs, I would suggest having an expert from YourMechanic come to your home to diagnose your AC system and help you fix it accordingly.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. When I turn the AC on, it makes like a rattling noise under the hood. As I keep the AC on, the sound gets louder.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Rattling noise AC heater

Hey there, thanks for writing in about your 2010 Lexus HS250h. Even though you said the blower motor looks okay, my guess is that it probably has a bad bearing, which is causing the noise. The only other thing I...

Q: Rattling noise upon starting and then louder rattling at idle if load is placed on engine such as A/C

Hi there. Given your mileage and your maintenance of the idler pulley, your problem is likely worn/weak hydraulic lifters (or other valve train wear) or the timing gear set. Starting the engine briefly (less than 30 seconds) without the serpentine...

Q: Where is the starter located in a 2013 Chevy Sonic?

You will need to have the battery jump started to see if the rapid clicking is due to a low battery or a theft light staying on causing the no start. For the starter location you would need to submit...

Related articles

What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.