Sucking/Whistling noises at 2-3K RPM

[P11]

As some of you know, I've been on searching for a resolution to solve my whistling issues between 2-3K RPM at 50%+ throttle. Originally this issue was non-existent, it only presented itself after a full overhaul of all associated intake manifold gaskets/ccv/vacuum lines. Now that the intake system was under proper vacuum and suction levels a whistling noise can be detected from inside the cabin between the 2-3K RPM range. After searching though my copy of BMW DIS I found some service information that seems quite promising, but I can't seem to make sense of it. (part number's cannot be found either)

The repair process consists of shorting the air intake by-pass hose, and inserting pressurized foam in the left sidewall cavities.

Repair Instruction DIS #: 1371000
Pressurized Foam Bottle Part #: 83429410694 (RealOEM cannot find it)

http://i2.photobucket.com/albums/y48/p11/IMG_0161.jpg

http://i2.photobucket.com/albums/y48/p11/IMG_0162.jpg

http://i2.photobucket.com/albums/y48/p11/IMG_0163.jpg

Does anyone know exactly where this by-pass hose is located? In addition to how exactly it can be shorted by 30cm and still function?

[bimmerfiver]

I don't have a 540, but it's gotta be at or in the fender, which needs to be trimmed and then foamed around. Interesting. They want the air filter inlet hose trimmed and the fender inner foamed. It says above, "Let foam harden before installing bypass hose."

Yup at the inner fender.

[Mark@EAC]

"Pressurized Foam Bottle" sounds like something along the lines of "great stuff" foam insulation in a can. I do not recommend filling any areas of your car with that garbage either. It might be a quick fix for BMW to make a quiet car for a happy customer, but that foam holds moisture and will make ideal conditions for rust development in that area.

[Jason5driver]

Seems to be a half-@ssed job from BMW to me.
Fix it right!

[P11]

Are there any alternatives? Would just shortening the bypass tube work?

[bimmerfiver]

Seems to be a half-@ssed job from BMW to me.
Fix it right!

See your local certified BMW mechanic. tm


:D

[AnotherGeezer]

The old E39 sucking chest wound

[P11]

Is the by-pass tube the small hole that is located in the upper section of the airbox? If so, does anyone know if this tube is removable?

[BrandonWA]

I had this issue on my 2000 540. But I had the Dinan intake. I always thought it was the intake silencer causing the whistle.

[BimmerBreaker]

I love how OP has asked the same question like 20 times and nobody has responded

Seeing as how nobody knows where this hose is why dont you look for a hose on the front right (M62) or front left (M52) of your engine?

It will be shaped like this:
http://i2.photobucket.com/albums/y48/p11/IMG_0162.jpg

Cut it and be on your way

[P11]

I just finished this job up (sans the foam). Took about 10 minutes, the bypass tube was actually MUCH better then I expected. Once removed from the fender housing I proceeded to cut where directed with an exacto knife. Reassembly was very easy as the tube was now much shorter and didn't have to be forced in.


http://i2.photobucket.com/albums/y48/p11/IMG_0168.jpg

I was wondering if there would be any ill effects to plug this hole up completely, seeing as it's above the filter some air would escape instead of being directed towards the intake manifold.

*I'll report back with results after I come back from the gym.

Whistling has been reduced by about 50%, I'm still entertaining the idea of using foam to insulate the rest of the fender. I just read up on closed-cell foam which is very resistant to moisture and mold development.