# Auto air conditioner

**URL:** <https://community.cartalk.com/t/auto-air-conditioner/17778>\
**Category:** Maintenance/Repairs\
**Created:** [August 6, 2008, 7:44pm UTC](https://community.cartalk.com/t/auto-air-conditioner/17778 "2008-08-06T19:44:12Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Howard11](https://avatars.discourse-cdn.com/v4/letter/h/ecb155/32.png) [@Howard11](https://community.cartalk.com/u/Howard11)\
**Post date:** [August 6, 2008, 7:44pm UTC](https://community.cartalk.com/t/auto-air-conditioner/17778/1 "2008-08-06T19:44:12Z")

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Our 97 T 100 has developed a whistle (when the air conditioner is turned on) that is heard in the cab. Is this a serious $ problem ???

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**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\
**Post date:** [August 7, 2008, 12:36am UTC](https://community.cartalk.com/t/auto-air-conditioner/17778/2 "2008-08-07T00:36:08Z")

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Does it do it when the fan is on, but not the A/C? Could it be a belt noise?

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [August 7, 2008, 12:42am UTC](https://community.cartalk.com/t/auto-air-conditioner/17778/3 "2008-08-07T00:42:59Z")

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The whistle might be from a defective expansion valve for the A/C when the refrigerant is converted from a high pressure liquid to a low pressure gas in the evaporator.

Tester

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**Author:** ![Beadsandbeads](https://avatars.discourse-cdn.com/v4/letter/b/c57346/32.png) [@Beadsandbeads](https://community.cartalk.com/u/Beadsandbeads)\
**Post date:** [August 7, 2008, 12:47am UTC](https://community.cartalk.com/t/auto-air-conditioner/17778/4 "2008-08-07T00:47:01Z")

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Does the sound change with the ac fan speed? If so, it could be a leak in the weatherstrip somewhere.

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**Author:** ![billsr412](https://avatars.discourse-cdn.com/v4/letter/b/ebca7d/32.png) [@billsr412](https://community.cartalk.com/u/billsr412)\
**Post date:** [August 8, 2008, 2:01am UTC](https://community.cartalk.com/t/auto-air-conditioner/17778/5 "2008-08-08T02:01:14Z")

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have you noticed a change in the sound when you are setting inside and windows are up vs down . could it be a window or door gasket ? turn a/c to normal and back to max with windows up couple times ,see if noise changes , if it is cab noise