Mazda Protege5 2003 a/c works well but is squealing. The noise changes when turning a/c on and off. The belt is new. So I'm checking the a/c pulley's bearing.

When a/c clutch is not engaged (a/c off), the pulley does not spin freely by hand like in this video or this video. It spins but there is great resistant. Is it because of bad bearing? I could not find any video showing that bad bearing makes hard to spin, can somebody also link a video?

  • Even though the belt is new, it can still squeal if it hasn't been tensioned correctly. Check the tension. Also, with the car running and aircon on, spray the belt with water and see if noise disappears. Also, you said the noise changes when turning a/c on or off, but can you clarify how? Does the noise disappear when a/c off for example?
    – NetServOps
    Jun 16, 2021 at 2:08
  • When turning a/c off, the squeal reduces and sometimes go away. I'm surprised because all the videos I found, they said spin the pulley to check the bearing noise. But if pulley is not spinning freely in order to check the noise, is it because of the bearing?
    – lucahuy
    Jun 16, 2021 at 2:48
  • It does point to the bearing failing. It would make sense because the noise reduces or goes away when you turn the a/c off, which is when the a/c clutch disengages the compressor. An issue with the clutch can have similar symptoms, but I would lean towards the bearing being the issue based on your description.
    – NetServOps
    Jun 16, 2021 at 3:39
  • So what else could I do to confirm that the bearing is failing? I can remove the pulley out of the a/c then try to spin, would that help?
    – lucahuy
    Jun 16, 2021 at 3:54
  • The symptoms you describe are enough to narrow it down to the bearing or clutch. The next step is to replace them, I would replace the clutch as well. You can get clutch replacement kits that contain the bearing and some other parts for around $75 (I did a quick google for a kit that suits your car). I could write a thousand words on how to do the replacement but this video will show exactly what to do. Its not difficult to do if you have even basic tools. youtube.com/watch?v=fe_y7kgM4Rk
    – NetServOps
    Jun 16, 2021 at 4:26

1 Answer 1


I replaced the bearing and the squealing is gone.

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