Q: Humming noise

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No warning lights have come on and car runs fine. It recently started making a 'revving' or humming noise when I start the ignition. Noise goes away by 20-30 mph and is intermittent.

Today radio stopped working and car asked me to enter security code.

Not sure if these 2 problems are related and may indicate a more serious problem.

My car has 181000 miles.
My car has an automatic transmission.

It is possible that you could be having an issue with your alternator bearing. The alternator is responsible for charging the battery and is ran by the serpentine belt.

The pulley that is connected to the alternator has a bearing that can dry out and make a humming sound. The best way to resolve this issue would be to replace the alternator.

I would recommend having a certified technician, like one from YourMechanic, diagnose the noise firsthand to determine if it is truly the cause of this issue. They’ll be able to replace your alternator as necessary if it’s proven to be faulty and address the issue with your radio as well.

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