Engine whine

[Tomk]

Hi All
is this an air leak or something else?
there’s a whine noise once the engine is up to temperature.
You can hear it for a few seconds once the engine is turned off.

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The cars had a new in take tube, pcv, cam and crank sensors.
Going to try and do a smoke test later.
Cheers

 

[elevensies]

sounds like fuel pump, really hard to tell on a video.

 

[Tomk]

sounds like fuel pump, really hard to tell on a video.

It’s not the fuel pump, definitely the noise is in the engine bay. Really hard to record but you can hear it clearer

Only happens once the engine is hot. Or at least it’s the only time I’ve heard it.

 

[t-tony]

Try it again with aux belts totally removed. Watching the video, the noise stops as soon as the cooling fan stops moving.

Tony.

 

[Tomk]

Try it again with aux belts totally removed. Watching the video, the noise stops as soon as the cooling fan stops moving.

Tony.

If you remove the aux belts what powers alternator, water pump etc? Or am I being dumb?
The only thing I didn’t replace when I did the water pump and belt etc was the tensioner. Guess it could be that.

cheers

 

[t-tony]

It will start and run without alternator working and w/pump for a short while with no issues.

Tony.

 

[Tomk]

Ok so noted today that if I remove the oil filler cap the noise goes away.
So is this an indication of a possible air leak? Ie pressure related?

 

[Nodzed]

A whine from a Z3 engine after shutting off, which disappears when the oil cap is removed, likely indicates a problem with the PCV (Positive Crankcase Ventilation) system or potentially a vacuum leak. The PCV system is responsible for regulating pressure within the engine crankcase, and a malfunction can cause this type of noise

 

[Tomk]

A whine from a Z3 engine after shutting off, which disappears when the oil cap is removed, likely indicates a problem with the PCV (Positive Crankcase Ventilation) system or potentially a vacuum leak. The PCV system is responsible for regulating pressure within the engine crankcase, and a malfunction can cause this type of noise

I have a look, but fitted a new one about a year ago. Guess something could have found its way loose. Thanks