Mystery noise, help please

[GrahamG]

My '04 Ls430 [85,000miles] has an intermittent murmuring noise which can be heard up to 30mph and is apparent only when the car is moving including in reverse [not when revving the engine in neutral and stationary]. It continues when coasting in neutral.

It is intermittent like morse code but softer and lower register. No it does not say, 'I am locked in the boot'.

Its is not affected by moving the steering wheel,  applying brakes, A/C on or off or the engine RPM.

Perhaps it started when my telescopic steering function failed recently. The fuse was pulled with the wheel in a good position which kills both rake and tilt motors. 

Difficult to say where it comes from other than in front of the driver but it is quite a distinct sound so I am hoping someone knows.

 

[NemesisUK]

My first thought would be tyres?

[sorcerer]

Can you record it?

What do you mean by "The fuse was pulled *with the wheel in a good position*" and has it really 'killed' both motors?

[dendonc]

6 hours ago, GrahamG said:

has an intermittent murmuring noise which can be heard up to 30mph and is apparent only when the car is moving

If you record it then upload to youtube & then put a link to it on here it would be much easier, for me at least, to attempt to identify the specific noise.

[GrahamG]

I should have said the noise is much too soft and gentle to record against all the other background noises without specialist kit.

When the telescopic motor fails a remedy is to move the steering wheel to a good position for driving then remove the fuse which kills power to both motors. I explained this had been done in case anyone thought the noise might be from either motor.

If I had to guess I could imagine some sort of servo driven vent or flap behind the dash associated with the heating and ventilation. Had hoped it would stop when switching off the A/C but of course other functions continue.

Cabin air filter replaced.

This is such a distinctive sound that if someone else has experienced it they will immediately remember.

Thanks for the replies

[sorcerer]

32 minutes ago, GrahamG said:

I should have said the noise is much too soft and gentle to record against all the other background noises without specialist kit

In that case then, turn the radio up 

[messi]

It could be the bushes on the air suspension pump. They make a noise when the bushes are perishing 

[GrahamG]

Qamar, thanks for that suggestion which must be a possible.

Not vital and not expensive so puts a smile on my face.

[messi]

No problem, they are about £12 for all 3

[GrahamG]

To answer my own question it appears to have been the front brakes.

I renewed the front pads [the originals were not bad] and the noise has gone, certainly 90% gone.