It’s a 2009 Honda Civic, LX Coupe 5-Speed AT, 1.8L L4 SOHC 16V.

The problem is a low, rumbling, vibrating sound, almost like an overly bass system or a muffler. The noise is most pronounced when the engine is cold at about 2000 RPM. But it never goes away completely. Also, the noise cannot be heard from outside of the car, but it’s very pronounced in the inside.

Here is a sound recording of the noise (listen on a powerful stereo system or with bass boosting headphones): CivicSOUND.wav

And here is a video (the audio quality is better in the sound recording though): CivicSOUNDvideo1.mp4

What could be the cause of this? Thank you in advance!

  • Assuming the car is stationary?
    – CharlieRB
    Nov 28, 2016 at 15:55
  • Yes, I recorded the audio and video files in a stationary car.
    – Vykintas
    Nov 28, 2016 at 18:49

2 Answers 2


That sounds to me like it is vibration from a loose exhaust heat shield, but it is impossible tell for sure. You will need to inspect for loose heat shields, fairings, air dams, exhaust pipes, etc.

Considering you said it can only be heard inside the car, look for components that are touching the floorboards under that car (exhaust, engine and transmission).

  • I’ve just had all the possible causes you mentioned checked at the authorised Honda service centre. They haven’t found any problems. So this noise remains unexplained. Thank you for your reply anyway!
    – Vykintas
    Dec 6, 2016 at 13:24
  • Did they have any guess what is causing it?
    – CharlieRB
    Dec 6, 2016 at 14:11
  • No, they didn’t have any substantial guess... They were checking all of the car for 4-5 hours, without success though.
    – Vykintas
    Dec 6, 2016 at 15:11

The problem was a broken motor mount.

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