406oc.co.uk

Hello everyone,

After a sad story with my previous 2.2 HDI saloon semi-mux 2001 (severely crashed by my wife), I currently drive an identical 2001 semi-mux 2.2 HDI saloon which, among other minor issues, has one which is really annoying. At high speed highway (above ~90mph/145km/h - I usually drive steady 170km/h) the car develops a whistle sound which becomes more intense and disturbing the higher the speed... Initially I suspected it might be related to a rollbearing but when I noticed the noise depends also on lateral wind (according to wind direction the noise becomes more or less intense) I had proof that the issue is related to aerodinamics.
I checked all doors 'uncovered' holes, doors sealings etc but nothing relevant was identified. The only difference to the previous 2001 saloon I owned is that the current one has a rear OEM wing on the luggage compartment hood and also the engine shield is not installed at all. Could one of the 2 be the cause? It's a really annoying noise and I have no other hints to follow

Thanks in advance.

So you're not actually able to tell where this whistle comes from? I don't think a rear wing would do that and neither of mine had an undertray. My D8 did whistle from the driver's door seal though...

Get your wife to drive it ( ) while you have a good listen all around the inside of the car, my guess would be the strip at the bottom of the glass on the front doors.

Does it have a roof rack?

GingerMagic wrote:Does it have a roof rack?

Good call, mine whistles like buggery when I have the roof bars on it.

steve_earwig wrote:So you're not actually able to tell where this whistle comes from? I don't think a rear wing would do that and neither of mine had an undertray. My D8 did whistle from the driver's door seal though...

I also assumed that neither the rear wing nor the lack of engine shield could cause it but these were the only differences to the old car. The doors seals look good though...

GingerMagic wrote:Get your wife to drive it ( ) while you have a good listen all around the inside of the car, my guess would be the strip at the bottom of the glass on the front doors.

Does it have a roof rack?

The 'wondering' sign about the wife driving it is referring to crashing the car again? ) Actually the first car she crashed under heavy snowfall, so it's not the case this time. But in any case I couldn't convince her to raise the speed until the whistle start threshold which is almost 100mph )) Her top speed is like 85mph
And no, the car has no roof rack. The window strips also look good.


Today I had another drive on the highway and took advantage that there was a faster guy (BMW 530D ) in front of me, so I could follow him while being protected of 'instant-on' speeding controls. I raised the speed up to ~210km/h (~133mph) and it seemed the noise disappears above 185km/h. So it starts to be heard lightly at around 155km/h, the irritation due to the noise peaks at around 170-175 and disappears at 185. Initially I thought above 185 it is covered by engine, normal wind and wheels noise but since between 155 and 180 the whistle increases in volume with speed it would have been normal to raise the level also above 180-185...
Anyway, my next move is to buy a wide sealing tape, go again on the highway, spend 10 minutes for sealing all the doors and windows except the driver window - left open to allow me to get in/out and test again . Then seal also driver window and unseal the passenger one. If the noise disappears I gradually unseal a component, test again and so on... Who knows, maybe I'm lucky and find quickly the root cause...

Tested today with left doors/windows/seals covered with wide sealing tape - no good result. Same test with right doors - no result. Tried also to seal the windshield sides - no good result.

The only idea I have is to try to remove the antenna and check again

After 6000miles of driving with the annoying whistle the issue is finally solved!

I replaced the antenna with the one from my wrecked 406 and no more whistle. It is strange that the old antenna doesn't have any small holes where air could cause noises but it is certain that the 'new' one solved the problem