Noise on acceleration with video added - NOW FIXED

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Bbr92

Member
I have this annoying squeak that I get every now and then when accelerating hard. I have narrowed it to a possible air leak and coming from the passenger side of the car. I have checked all of the air pipes on that side and everything is fine. Having taken it all apart the only thing that appears to be strange is the pipe that goes into the left hand side of of the sound generator (i.e before it) has a jubilee clip that is tight however the pipe isn't actually long enough for the clip to work. So the only thing really holding the pipe against the sound generator is the tension between it and the generator intake. The question I have is does any air that could possibly cause this squeak get as far as the sound generator or is it purely just the noise?
 
Possibly the boot that connects to the sound generator leaking air but tends to be a whistle on acceleration. Check the discussion about leaking rubber boot started yesterday it was just above yr query an has the part nos in it as well. It's usually the small corrugated pipe that perishes :thumbsup:
 
Bbr92 said:
does any air that could possibly cause this squeak get as far as the sound generator or is it purely just the noise?
Click to expand...

Part of the generator is open to intake air, so in theory leaked air could reach the generator, but in practise the generator chamber is under negative pressure so any leaked air will continue into the engine rather than enter the generator. However, any noise generated can enter the generator, good or bad, and it will be transmitted into the cabin. Sound can travel where air cannot, except through an absolute hard vacuum.
 
Ok thanks so in affect if the pipe that enters the sound generator, air box side isn't a tight fit a possible air leak could occur?
 
Absolutely. That connection needs to be air tight. Sounds like the boot with side inlet had been replaced before and they did a poor job installing the new part. As scousefly mentioned, that part is a common failure.
 
Went to the garage today and they did a smoke test and found a small leak so fixed that and thought it was all fixed and on the way home the bloody noise has come back!! I will take it back to the garage again but made a video so thought I would post on here to see if anyone has any ideas? Noise happens when I start to accelerating hard in low gears and sound like a faint car horn, you can hear the noise at 4 secs and at 13 secs.

Any ideas would be great as its really bugging me.

[youtube]HDMHXVZewBU[/youtube]
 
That's a queer noise! No wonder you're annoyed! Are you sure it's not inside the cabin? Such as the pedal assembly? On M54s it could be the throttle body, these should be cleaned once in a while anyway. On N52s it could be something in the valvetronic mechanism.

I've no real reason to suspect these things, but on my crappy speakers it sounds more like parts rubbing rather than a reedy air leak noise. Only you are in a position to distinguish between the two. Hopefully by now you've resolved the issue, but just in case...
 
2 weeks ago got the oil and filter changed in my autobox and since then no noise at all. Just in case anyone else ever gets this problem. Thanks for all your replies and possible fixes
 
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