AC compressor bearing ?

[Iftekar]

https://youtu.be/usArPwsRZDE

Hello Guys,
Rather than trying to explain the noise, I thought of uploading a clip. So please watch that clip first.

Initially I thought it was the tensioner or the belt. But both of them were replaced 10 months ago including the other two idler pulleys. No oil leak that can cause belt slippage. On a Visual inspection, belt and tensioner looks good.
The noise starts only after 2000 rpm and prominant around 3000 rpm. Doesn't increase much with higher rpm but it does a tiny bit. At idle- no noise. Exactly same behavior when the tensioner gone bad 10 months ago.

My trusted mechanic friend told me its the ac compressor. He asked me to switch on the ac and try pushing the pedal to 3000 rpm- indeed there was no noise( well extremely fainted noise). With ac off- noise is present.

While I don't doubt his knowledge and expertise, I am here to get some suggestions.

1. Is there anything else I can test to confirm it's the compressor?

2. Could it still be the tensioner or the belt ?

3. My friend said, it's okay to drive until the noise is more. Note- the noise is heard from inside the cabin only when everything else is quiet.
Is that the advice you guys also suggest?

4. How difficult is it to replace the compressor. I can change plugs, coils , charge pipes and few other stuffs.


2011 BMW 335i E93 (N55) with 112k miles on it. Car runs perfectly fine otherwise.

Thank you so much guys.


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[jclausen]

You could get second opinion from a BMW shop I don't think it's hard to replace, it's my understanding that the new style compressor does not work like older style designs like on my e39. The reason I mention that is because the new style compressor could be damage when you turn it on for the first time if proper procedures are not followed.

[bms5]

If the pulley bearing is dry and failing it could certainly sound like that. When the a/c clutch engages, load on the pulley bearing changes as it is now connected to the entire compressor shaft assembly. Use a mechanic’s stethoscope to pinpoint it to the compressor.


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[Iftekar]

Thanks everyone.
Strangely today morning when I was checking for the noise- it's even present when the ac is ON. Although fainted and not as pronounced when the ac is off.
I think I am goin to remove the belt and replace(if required)- I will get better access to check the pulley.

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[Iftekar]

https://youtu.be/zXBBxgDkQSc

https://youtu.be/ovNbPCfNnT4

Some more video. Does that tensioner pulley looks okay ? Seems like its wobbling a bit.

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