E39 whistiling noise - from intake?

My '99 528i has developed an annoying whistling noise that seems to be
throttle-postion related. It occurs at many speeds and RPM's, as long
as the throttle is at the cruise / light throttle position, and
literally sounds like the throttle valve is cutting the air and making
it whistle. Moving the throttle just a bit in either direction
eliminates the noise but, it happens to occur exactly at cruising
throttle postion so I hear it all the time.

The dealer rode with me and heard it easily, and acted like it was
very peculiar, but when I picked the car up after leaving it to have
this repaired I was told that this was "normal" and that "they all do
that once they get some miles on them" (75k on mine). They have no
recommendation other than "live with it." I find this difficult to
accept, especially since it didn't use to do it. It has come on
slowly over the past several months and now is quite annoying. Does
anyone know if this noise can be eliminated? Or if this is actually
what it is? The car is under BMW's extended warranty.

Sounds like the service information # SI 110298286 relating similar
whistling noise cause by :
Flowing noise at the throttle valve, transmitted into the vehicle interior
via the by-pass hose (intake filter housing) and the body (support carrier).
remedy :
Shorten the by-pass hose and line the front left (m52 engine) sidewall with
foam.

This was supposed to be fix at the line since feb.98. Your 528 could have
been built anywhere from 06/98 to 05/99 to be a 99 model, that service
information should'nt be applicable, but who knows.... it's only an half
hour job.
Talk about that one to your dealer and if he don't want to do anything,
contact BMW directly to complain.

Good luck



"dave" > a écrit dans le message de news:
...
> My '99 528i has developed an annoying whistling noise that seems to be
> throttle-postion related. It occurs at many speeds and RPM's, as long
> as the throttle is at the cruise / light throttle position, and
> literally sounds like the throttle valve is cutting the air and making
> it whistle. Moving the throttle just a bit in either direction
> eliminates the noise but, it happens to occur exactly at cruising
> throttle postion so I hear it all the time.
>
> The dealer rode with me and heard it easily, and acted like it was
> very peculiar, but when I picked the car up after leaving it to have
> this repaired I was told that this was "normal" and that "they all do
> that once they get some miles on them" (75k on mine). They have no
> recommendation other than "live with it." I find this difficult to
> accept, especially since it didn't use to do it. It has come on
> slowly over the past several months and now is quite annoying. Does
> anyone know if this noise can be eliminated? Or if this is actually
> what it is? The car is under BMW's extended warranty.

Thank you. It sounds like this fix is aimed at reducing the throttle
valve noise that gets into the vehicle, rather than actually
eliminating the noise. Do you agree? I will definitely look into
this, but are there any ideas about eliminating the noise at the
source?

I thing that the way they cut the by-pass hose to shorten the lenght of it
probably reduce significaly the noise and the foam muffled any remaining
one, but not 100% sure. I'd like to say that it's a design flaw, but the
real question is why some car make no noise while some others do. Maybe it's
related to the aerodynamic of the car because that S.I apply to all e39, 6
cyl. & v8. The v8 get it's air from the right side compare to the left side
for the 6 cyl. model. When they assembled those cars maybe some were built
to the low (or high) side of "tolerance fitting" and did all the difference,
I don't know. I own a 1997 540i manual (no modification done for that
related problem), and I don't have any whistle. Saying that, there's another
source of whistling problem that is not related to the engine,(and I got
that one) but happen at some speed. There's 4 jack pads (black square
plastic) underneath the car and the 2 up front are really important because
if one or both are missing the air goes through the hole (receptacle of the
pad) and a whistle sound goes all along the A pillar to the interior of the
car. I'd lost 3 of them (probably in winter time) and when I replaced them,
I carefully clean everything and put a bead of sillicone on the pad before
installing it. I'd never heard anything since then.(2-3 years ago). That all
I can say...

good luck

"dave" > a écrit dans le message de news:
...
> Thank you. It sounds like this fix is aimed at reducing the throttle
> valve noise that gets into the vehicle, rather than actually
> eliminating the noise. Do you agree? I will definitely look into
> this, but are there any ideas about eliminating the noise at the
> source?