High-pitched "whirring" following gear change

[xsara92]

I have heard this noise, I feel, on several (almost new) hire cars and now it's there most of the time on my Xsara Picasso...

After changing gear, either from 2nd to 3rd or 3rd to 4th, I hear a high-pitched noise, not a whistle but more of a grating, whirring (I know, describing sounds).

I attempted to record it but can't capture it with background noise.

What I'm wondering is whether it could be
- the turbo
- the gearbox
- fuel / oil pump

Or some other part of the engine or drivetrain.

The car has 109k miles.
It has been regularly serviced. Oil change is due. Is a worn turbo likely? Yet as long as I time gear changes well, I have fairly mimimal reduction in acceleration.

I'm interested almost as much as worried about what it could be.

[mickthemaverick]

If it begins as you release the clutch and lasts for a few seconds I would suggest it is your clutch release bearing winding down after use.

[xsara92]

Thanks does that mean the bearing is worn?
The clutch was changed at 95k

[mickthemaverick]

Probably yes, worn or running out of line which is the same difference. Was the bearing renewed with the clutch and was it a good quality part?

[PaulC5]

Does slightly touching the clutch pedal make any difference to the noise as one check on the release bearing ?
We had a turbo fail on a petrol Saab and the early signs were smoke on accelerating due to oil getting passed the seals. When it did fail on the M6 at Shap, it became a bit noisy and when I got to the Penrith junction the car became surrounded in white smoke so was recovered by the RAC's contractor.

[xsara92]

Hi Paul I road tested again and I think the answer to your question is 'no'. For example if I stay in 3rd or even 4th (on an A road) roundabout I've heard the noise still.
I'm leaning strongly towards thinking that the noise comes from the oil circuit, as the oil nears the end of life.
I wonder if a turbine with play to the shaft could make this noise.
The only evidence that could point to the transmission rather than engine is the noise most often being loudest when I am applying a near constant power before increasing revs up towards the next gear change - this is probably my driving style

[PaulC5]

A link on turbo whistle noises which might be normal https://aet-turbos.co.uk/the-turbo-whis ... explained/

[xsara92]

OK, I just want to clear up this thread.
In the end, the cause of the noise was the gearbox oil level.
I finally had this topped up two days ago, have now only heard the noise once very faintly over about 100 gear changes so far!

I realise now that 'whirring' was not the best word for the noise. 'Whining' would have been accurate.
I've checked the noises made by a bad clutch release bearing on YT, and indeed this seems to be more of a mechanical noise like a shuffle or whirr.

The gearbox oil was lower than full because 18 months ago, I had one drive shaft seal fail.