# Whistling AC

**URL:** <https://community.cartalk.com/t/whistling-ac/65233>\
**Category:** Maintenance/Repairs\
**Tags:** noises, airconditioning\
**Created:** [June 5, 2011, 1:46pm UTC](https://community.cartalk.com/t/whistling-ac/65233 "2011-06-05T13:46:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lbl03c](https://avatars.discourse-cdn.com/v4/letter/l/bbce88/32.png) [@lbl03c](https://community.cartalk.com/u/lbl03c)\
**Post date:** [June 5, 2011, 1:46pm UTC](https://community.cartalk.com/t/whistling-ac/65233/1 "2011-06-05T13:46:06Z")

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I had this same problem in my toyota celica recently. I discovered that it was the air vent making the whistling noise. I had closed the vent, or so I thought. Due to age, the vent is a little loose and so when I had it “closed”, it was actually open just enough to create the sound. After some fiddling with the vent opener, I managed to make the noise go away.

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**Author:** ![jreagan](https://avatars.discourse-cdn.com/v4/letter/j/4da419/32.png) [@jreagan](https://community.cartalk.com/u/jreagan)\
**Post date:** [June 7, 2011, 2:14pm UTC](https://community.cartalk.com/t/whistling-ac/65233/2 "2011-06-07T14:14:24Z")

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The whistle is mostly likely coming from the A/C expansion valve. My 07 CR-V did the same thing (Honda had a TSB on it). The sound is coming from the refrigerant expanding in the valve and whistling just like blowing across the top of a bottle.