I've started to notice that there's a high pitch hum or ringing (sort of like a high pitch ringing in your ears sometimes) when the engine is running. And when I turn off the engine it's like turning off the vacuum cleaner (don't know if its related to the high pitch sound). Is there something I should be worried about? I've attached a photo of what region the high pitch sound comes from. The car is a 2001 Holden Astra sedan.

  • Could the "vacuum cleaner" noise be the radiator fans turning off? Feb 19, 2016 at 10:24
  • I think not, because you can hear it even when you just turned off a cold engine and the fan didnt spin.
    – ints
    Feb 20, 2016 at 22:21
  • Defective fans can work when engine is cold, but you should clearly see them spinning. Feb 22, 2016 at 9:54

1 Answer 1


Sounds like you might have a vacuum leak. Check all the vacuum lines in the area. Some electronic components can also make a high-pitched whine when they start to fail, but the only ones I'm familiar with that do that are flyback transformers and high-current power converters, and I don't believe a car would have any of those. That said, it might be worthwhile to find out if the vehicle's ECU or other control units are in the area, and check to see if they're making any noise.

  • Alright, appearantly ECU was one of the common issues with this model. Could it be something to do with the power steering components? As far as i know it has an electric-hydraulic power steering.
    – ints
    Feb 20, 2016 at 22:23

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