High-pitch whistle when accelerating

[Thork]

Is a quite simple fix actually, the whistle is coming from a crack on the ruber hose for the idle valve on the lower boot that conects the trotle body to the air intake. The part itself is around $50 and it will take no more than 15 min to replace, NOW I got mine replaced under warranty (good will repair ) and for what I got from the tech the new part has been improved. The part is the #5 on the diagram

http://www.realoem.com/bmw/showparts.do?model=BT33&mospid=47798&btnr=13_0995&hg=13&fg=15

I just noticed mine cracked two days ago. I'm ashamed I never noticed it before. I just got the call that my part came in, but I won't be able to pick it up today because I don't have the time . Glad you posted this. If you go take a gander at my thread
http://www.z4-forum.com/forum/viewtopic.php?f=3&t=5592 I posted a pic of the cracked hose. It seems like a straightforward R2 so I'm doing it myself.

Yeap, is exactly the same and is a pretty straightforward replacement, said that, I took mine to the dealer as matter of principle, that piece of rubber shouldn't fail in that way in a car with only 68k miles, and now (from yours and others post) it seems is a common failure

 

[veryhuman]

Could dust get into the engine thru the crack this way?

 

[dfrangipane]

You're not by any chance playing a 'Slim Whitman' cd are you?

 

[Aebous]

Yeap, is exactly the same and is a pretty straightforward replacement, said that, I took mine to the dealer as matter of principle, that piece of rubber shouldn't fail in that way in a car with only 68k miles, and now (from yours and others post) it seems is a common failure

Ok, just got done R2'n mine, like you said, it is a straightforward replacement. Took the car for a quick test drive around the block, the cracked hose was definitely a contributor to the whistle, the cracked part was a lot louder before replacement. Now I notice a whistle but it's quite faint, which with the radio on I doubt I'll even notice now. Same situation though, reckon I'll be grabbing a mirror and looking at the rest of my hoses as well.

 

[Thork]

The whistle in my car is gone, the new boot took care of that problem. In your case I would ck that the air filter and air box lid are properly secure, that the air mass sensor is properly attach to the air box and that all the clamps are tight (a small gap can cause a whistle). Hope this help and good luck!!

 

[2003 Z4]

I am sure that I am a little late with this response but my 2003 has a high pitch whistle when I am crusing at a constant speed then slightly accelerate. If I floor it, the whistle will go away. If I let off of the gas, the sound will go away. I brought this up a few times at three different dealers. One dealer stated that the sound that I was hearing was the sound of the fuel pump. Mine is so slight that a passenger does not seem to hear it. I could not get the dealer to hear it! You have to be on a back road just cruising. You can not hear it with other traffic around you. I also had a hard time hearing it with the top up. My guess is that different fuel pumps make different sounds. This whistle can not be heard at idle which is when the dealer's listened for it. I have heard this for almost 3 years but everyone else thinks that I am making it up! I am glad that someone else has had this problem. If you are like me, you have never had a problem with the car because of this whistle.

 

[mystik]

2003 Z4,

i here this ghost whistle the exact same way you describe it. just ever so slightly when i have the accel. peddle on cruise. it vanishes as soon as i begin to floor it. i had my car check out numerous times for any problems and a lot of mechanics are saying that nothing is wrong my car. it's just paranoia.

in any case... my car's inspection 2 is comin' up in about 10k miles. i'll have one of my regular mechanics take a good look at my car while he works on it.

i'm hoping it is paranoia & nothing is wrong my ride*

 

[Nickyg]

Sorry chaps, been off the board for a while. Thanks for all the replies, very helpful. I have my Cat 1 service coming up in 500 miles so i'll mention it then as it is still under warranty.
Cheers

 

[ztothe4]

If you are standing in front of the car, looking into the engine bay, where is this defective piece. I have this same problem and it has been annoying me for a while now and would like to fix it. Thanks

 

[Aebous]

If you are standing in front of the car, looking into the engine bay, where is this defective piece. I have this same problem and it has been annoying me for a while now and would like to fix it. Thanks

To the right of the engine block. Follow the tube that comes off the air filter box and goes towards your engine. The "elbow" where it connects to the engine has seemed to be the trouble spot.

 

[ztothe4]

Well I went out and checked the piece this morning and sure enough it has a rip in it. Add me to the list of people that have experienced this problem.

 

[mlt]

I have this high-pitch whistle as well (2003 3.0i) as does my friend with his 3.0i, I always thought this is normal as these two are the only 3.0 Z4's I've ever driven.

 

[Aebous]

there is a "ghost whistle" that is normal.....I think you can get away with a search concerning it on this forum....some of us have found out it is more than simple whistle though. Bottom line, check all your vehicles hoses yourselves and make sure one isn't cracked or loose and that is what is causing your whistle.


*edit* or at least a dealer check your lines

 

[Nickyg]

Right, took the Zed for its Inspection 1 service and asked them to look into the whistling. They found a hole in the glove box where you can see straight through to the engine. Apparently some people have a kind of amplifier fitted to make the engine sound louder in the car? :|

They checked my chassis number and my car didn't have one fitted as standard so therefore the previous owner may have fitted one after-market then removed it? Very odd.

I am going to try and bung the hole up to see if it makes any difference. I'll report back when I do. I'll also check the pipe issue mentioned in other posts.

 

[Andrew D]

Apparently some people have a kind of amplifier fitted to make the engine sound louder in the car? :|

They checked my chassis number and my car didn't have one fitted as standard so therefore the previous owner may have fitted one after-market then removed it? Very odd.

I think they mean the Motor Sound System. It relays induction pulse noise to the cabin; standard equipment on all 3.0-litre cars (or at least M54B30, presumably post-facelift also), not an option on any other.

 

[Nickyg]

Had the car checked again today and they are going to put a bung in the hole for me. That arrives in a week so i'll see if it makes a difference.

 

[mystik]

just brought my car back from the shop.

the mechanic said everything is fine. it's just a faint whistle that it is normal for the car to make.

 

[Sephanite]

i dont know what the noise is about. but from my knowledge, if i accel with that noise (ie. 10-15%?) i get really good mileage. any more i see if i should down shift, any less i look on upshifting. i do this on flat roads and when i need to accel a bit. cruising my pedal is in too little to maket he noise