New engine sound

[thomasselboe]

Hello, recently I discoverd a new sound from the engine. The sound is best described as a whistling/whining sound. It almost sounds like an ambulance siren. The sound increases with the revs and is most dominant when the engine is cold. Anybody experienced anything similar. The engine is a 1.6 hdi with approx. 165 000 KM

[jj9]

The Turbo can make a sound like that.

Check that all of the air pipework is secure and not leaking and check the free play on the turbo. 


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[Sol]

As JJ says, if it rises suddenly when going on boost at around 1750 rpm it's likely to be turbo related.

If it goes all the way from idle, it could be the alternator bearing or the timing belt idler pulley bearing / tensioner bearing.

If you have a length of plastic tube, it can be used as a non contact stethoscope by putting one end of the tube to your ear and using the other end as a sound collector to identify where the noise is coming from while a friend holds the rpm at the point where the noise is obvious. Just be careful of moving parts.

When you point the tube end at the culprit, it should be much clearer where it is coming from.