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 October 17, 2016

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.

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