What is this noise?!

[power_of_dreams]

Hi all,

I've got a 06 CL9 and have been hearing some bizarre noises recently! It sounds like a high pitched fart/whistle that tapers off at the end. It's a very "airy" sound, like vacuum related.

In fact when I first heard it, I thought it was from the radio station, but the second time it happened the radio wasn't on. It appears to occur in hot conditions and from forward of the driver's seat, most likely the engine bay but not sure.

Most recent occurrence happened at the lights, so that probably rules out engine/brakes? Does not appear to affect performance of the car (as yet)

Any ideas?

[beeza]

U might check the exhaust where the catalytic converter is bolted to the exhaust. Could be a gasket there.

Any more info?

[Fredoops]

Power steering pump.

check the P/S reservoir see if you get bubble.

it's common to fail.

[beeza]

The dreaded p/s pump whine.

I got it atm.

Just swap it out with a known working one.

To check it's it,put a metal pipe to your ear the other on the ps pump.Use this method to find where the noise is coming from.

[u mad?]

i'd flush the rack/whole system if you can after the pump swap/rebuild, a failed pump can leave metal shavings all throughout the steering system

(assuming that's the issue in the first place)


get someone to turn the steering wheel while stationary and listen if the pump gets noisier under load

[power_of_dreams]

I have the power steering whine, but this sounds different. This is like one of those whistles where you pull the end and the sound changes (seriously!)

Starts deep but then gets higher pitched. Best description I can give. Haven't heard it since last time though.

[beeza]

Hmmmmm

Have you found anything on the net that it could be?

[power_of_dreams]

Nothing! I don't really know what to search for!

Still haven't heard it since, but it was also around last summer if I recall so it may be temperature related.

Going to sound crazy but basically it sounds like this: https://youtu.be/T-BTa7TdVYk @ 3 seconds (the first half only, so it goes from low to high but not back down to low)

[beeza]

That is weird. Thats a new one for me.

[Fredoops]

Check alternator voltage

[power_of_dreams]

I'm booked in for service, will ask my mech.

Doesn't sound electromechanical though? Definitely sounds pneumatic related? I would think that sound could only be generated by some form of air flow?

[beeza]

I swapped the ps pump and still got the whine. .

I'm thinking it's the throw out bearing in the gearbox.

Let me know how you go!

btw mine comes and goes,when it wants,you can hear it at idle and if you put the blinker on the sound changes in pitch with the blinker.Also it can be louder some days than others but not enough to annoy ya really.