# Can you tell me what is causing this loud noise when AC turned on? (Short video clip)

**URL:** <https://community.cartalk.com/t/can-you-tell-me-what-is-causing-this-loud-noise-when-ac-turned-on-short-video-clip/140891>\
**Category:** Maintenance/Repairs\
**Created:** [May 24, 2019, 1:11am UTC](https://community.cartalk.com/t/can-you-tell-me-what-is-causing-this-loud-noise-when-ac-turned-on-short-video-clip/140891 "2019-05-24T01:11:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![172slcs\_150026](https://avatars.discourse-cdn.com/v4/letter/1/f17d59/32.png) [@172slcs\_150026](https://community.cartalk.com/u/172slcs_150026)\
**Post date:** [May 24, 2019, 1:11am UTC](https://community.cartalk.com/t/can-you-tell-me-what-is-causing-this-loud-noise-when-ac-turned-on-short-video-clip/140891/1 "2019-05-24T01:11:42Z")

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I had the AC belt and AC idler pulley off for some time. I recently put it back on with a new belt.

When I turn on the AC on there’s this loud pitched noise. See short clip here: [https://youtu.be/ucJ\_VhZuefY](https://youtu.be/ucJ_VhZuefY)

At first, when the A/C was turned on and it made that loud sound the A/C belt would also turn really slow and then resume back to normal when turned off.

I took the A/C clutch off and removed a small shim washer to get it closer and it does not seem to slow down now when it spins, though the noise is still there and loud.

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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:** [May 24, 2019, 1:13am UTC](https://community.cartalk.com/t/can-you-tell-me-what-is-causing-this-loud-noise-when-ac-turned-on-short-video-clip/140891/2 "2019-05-24T01:13:38Z")

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The vehicle needs a new AC compressor.

Tester