# Lend Me a Tenor - My A/C SINGS to Me!

**URL:** <https://community.cartalk.com/t/lend-me-a-tenor-my-a-c-sings-to-me/44>\
**Category:** Maintenance/Repairs\
**Tags:** airconditioning, riviera\
**Created:** [May 24, 2007, 5:48pm UTC](https://community.cartalk.com/t/lend-me-a-tenor-my-a-c-sings-to-me/44 "2007-05-24T17:48:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Big\_Riviera\_1990](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/big_riviera_1990/32/43_2.png) [@Big\_Riviera\_1990](https://community.cartalk.com/u/Big_Riviera_1990)\
**Post date:** [May 24, 2007, 5:48pm UTC](https://community.cartalk.com/t/lend-me-a-tenor-my-a-c-sings-to-me/44/1 "2007-05-24T17:48:00Z")

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Back again folks! With another oddity of a question.  
  
  
  
 When I turn off my A/C system in my car (1990 Buick Riviera) after having run it, the A/C system whistles at me. This ususally lasts about ten seconds. It whistles with a note that grows in intensity and then diminishes and then grows, etc. It is rather high pitched and sounds as if I were doing the whistling myself (but I’m not, I’m not crazy.) When it’s finally finished the note bleeds off slowly for about a second.  
  
  
  
 It will also do this at idle.  
  
  
  
 I’ve never encoutered a singing A/C before so I’m wondering what it may be.  
  
  
  
 I have some theories but they’re as scatterbrained as I am.  
  
  
  
 Any thoughts?  
  
 Do I need to worry about this?  
  
 Is this a harbinger of black death on the horizon?  
  
  
  
 -Matt

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**Author:** ![willey](https://avatars.discourse-cdn.com/v4/letter/w/a9adbd/32.png) [@willey](https://community.cartalk.com/u/willey)\
**Post date:** [May 24, 2007, 7:45pm UTC](https://community.cartalk.com/t/lend-me-a-tenor-my-a-c-sings-to-me/44/2 "2007-05-24T19:45:20Z")

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Vacuum leak?

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**Author:** ![system](https://global.discourse-cdn.com/cartalk/original/3X/1/d/1d47c66a543aa6c5a7873bb2320858f978ff52ed.png) [@system](https://community.cartalk.com/u/system)\
**Post date:** [May 24, 2007, 8:22pm UTC](https://community.cartalk.com/t/lend-me-a-tenor-my-a-c-sings-to-me/44/3 "2007-05-24T20:22:50Z")

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It’s coming from the A/C system not the HVAC.

Sounds like it’s coming from the lines right in front of the firewall.

-Matt

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**Author:** ![Big\_Riviera\_1990](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/big_riviera_1990/32/43_2.png) [@Big\_Riviera\_1990](https://community.cartalk.com/u/Big_Riviera_1990)\
**Post date:** [May 27, 2007, 8:25pm UTC](https://community.cartalk.com/t/lend-me-a-tenor-my-a-c-sings-to-me/44/4 "2007-05-27T20:25:16Z")

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It turns out it’s a clogged orifice tube. As the refrigerant travels through at lower pressures and flow rates (eg. at idle or when equalizing after shutdown) it whistles as it passes through the orifice screens.

-Matt