strange noise from rear of car @ 4500rpm +

[darko]

this was weird....

this morning while accelerating hard in 3rd as i reached around 4000 rpm maybe a bit more a sound came from the back of the car which sounded like someone blowing over a milk bottle ! i slowed down and accelerated again and it did it again.. i tried in 2nd and the same noise - it was raining pretty hard but i dont think that would be connected ? anyone have any ideas ?

 

[jesters3]

High/Low spots on the tyre was one issue I found when I had a 'resonating' sound coming from the rear.

Or it could just be the road surface you went over?

 

[darko]

im going to try again tonight on the way home and see if it happens. almost certainly sounded like it was engine / transmission not road noise as i was able to make it happen again by accelerating to the same revs. almost sounded like the exhaust was blocked or something ! was wonderng if it was the haldex maybe as the torque transfered to the rear wheels ?

 

[benk]

You sure it's not the Diverter valve leaking? I thought people always said that sounded like a milk bottle being blown.

 

[darko]

not this time.. its fairly new and mine makes a fluttering when it its had enough. the noise was from the rear of the car, like the haldex was complaining or the exhaust was obstructed. tried to recreate it again last night and couldnt so must have been something to do with the rain...

/ubbthreads/images/graemlins/confused.gif

 

[242spot]

I have jiust developed the exact same noise im my car, its doing my head i have no idea what it is.
Makes it as the boost comes on strong and again when you take your foot off.
Def not tyres it sound mechanical dif or something.
Did you ever get to the bottem of it??????
Does anyone else have this ???

ps excellent decription had to laugh sound like someone blowing over a milk bottle.... blilliant i thought for ages for how to describe that!

 

[darko]

luckily it just went away however i dont generally like problems that just fix themselves...

on mine i am pretty certain it came from the back of the car but noises can be confusing and it MAY have have come from the engine

i have to admit my car sounds quite loud these days especially at idle so i have since wondered if it was a baffle in the exhaust that collapsed

the car has been remapped since and i would have thought this would have caused the noise to come back if it was the dif or something in the drivetrain

the car was thoroughly checked out before being mapped and on the 1st test run it managed to spin all 4 wheels in 2nd gear with no repeat of the singing milk bottle

 

[darko]

might be a good idea to get someone in the car with you to confirm if the noise is coming from the front or back

 

[242spot]

mine has gone away now. Only lasted half a day. strange ... i dont like noises that just go away.
oh well
thanks for the response