I have a Peugeot 406 Petrol (1.8 16V Engine).

When I sit in the car with the engine idling, I can barely hear a noise that I'm not sure where it is coming from.

I think it is similar to a bearing noise but I'm not sure. I opened the hood and listened carefully with a rubber hose (one end into my ear, the other end near any part that I suspect could be the culprit).

I checked alternator, idler pulleys, Belt tensioner, AC Compressor, Hydraulic pump and all around the engine but I didn't hear anything that sounds abnormally.

I thought maybe it comes from the gearbox but when I fully pressed the clutch (to prevent inner gearbox shafts from spinning), it made no difference.

The only thing that I can't inspect is the water pump bearing because it is inside timing cover and I don't have easy access to it.

What do you think about the noise?

  • please post an audio snapshot of the noise. – Moab Aug 7 '20 at 19:03
  • It is so low that I can't record it with any device. Some people don't hear it at all! – Nariman Asgharian Aug 7 '20 at 20:14
  • Ventilation fan? – Martin Aug 7 '20 at 20:51
  • No, I don't think it is ventilation fan because I changed its speed but the noise was still there. I turned the engine off and turned on ventilation fan but the noise disappeared! – Nariman Asgharian Aug 7 '20 at 21:28
  • Try opening just the right-side windows. Then open just the left side windows. Any difference? Then, with the brake on, load the engine while keeping the RPM slightly off-idle. – John Canon Aug 8 '20 at 5:38

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