Specific sound whilst reversing, steering hard left and tilting forward - what is the source

[Slepetau]

Hi.

Car: Year: 2009, 3L diesel 173hp, manual transmission, mileage 239 k km / ~86 k miles.
Environment: hot summer day about 25 degrees Celsius (normal temperature a lot colder).

First - recording from dash cam + overlay showing resequence spectrum with time marker:

Today is first time I encounter this sound. It's frequency is fixed at 1200Hz, so to me it seems independent on engine rpm or speed.

Any ideas on what can cause this sound? It seems to be triggered by the forward tilting of the car, possible in combination with steering hard left (not maximum) and reversing in low gear

Other than the sound itself, there was nothing else noticeable about the car. No decline in engine power, no vibrations, that sound only.

[edit]
adding sound time-line as spectrum - screen copy from Audacity.

 

[MisterCruiser]

I had fitted new brake disk splash guards to the front of my 120 a month ago and all seemed clear of the disc when I checked at the end just by spinning the wheel by hand in straight ahead position. However, when turning left on full or nearly full lock and on my sloping concrete at my house it it was catching.

I can't really make out your video noise, but just giving you the suggestion anyways.

Have you done or had any work carried out on your cruiser when this started happening, might help narrow it down a bit.

 

[Shayne]

Check engine mounts . But might this be the cruiser known to suffer an air box rattle ?

I don't know the 120 but i think a number of people had a problem with the intake hose rattling against the body where it passes through the wing . Worth a google maybe .

 

[Slepetau]

Hi, thanks for suggestion.

So the sound mentioned is not a "rattle-like" sound, but closer to a flute. In hindsight I see I forgot to crank up the volume on the YT video so the sound is probably not noticeable unless volume is turned up considerably - my mistake.

But yes - both front brake disk splash guards was replaced, about 2 years ago.

And yes - there is a rattle sound also (another issue probably) where intensity and "RPM" seems to be dependent on speed and jerky movement from uneven road. This I suspect originates from Megawheel centre cup - because when I mounted the wheels earlier this year, the wheel centre cup on right front side did not put stuck as on the other wheels.
But thanks for suggestion on air intake, will check this out.

 

[Slepetau]

Update.

Car was visiting workshop yesterday and it was found that the brake shield needed to be moved slightly. The car is still on workshop, but for a different issue (I make a new post about that)