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XXXXXXXX
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Discussion Starter #1
Ok I have a 2001 Z3 2.5I with 32000 miles and I have a strange annoying whistling noise from the engine?
The noise is changed with accelaration and is only present at or around quarter throttle. If you give it a little more gas when you here the wistling it will go away or if you let off the gas a little it will go away. The wistling is rather loud and sounds like air going through a throttle body? It has done this since I bought the car a month ago and only at the low rpm.
Anyone had this issue or heard of it?
I thought it my go away when I changed from the stock air cleaner to the Dinan CAI but same.

Thanks
 

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I think it is the air intake located under the hood. Mine makes a similar noise and have been told it is normal for it to do it. I can only hear it as you describe but only when I have the top down and no music on.

Not sure there is anything you could do for it, if anyone knows post a recommendation.
 

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Carpe Diem
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I had the same problem with my M roadster 2002...it sounded like it was coming from the front but indeed was comin from the rear. Ended up being the fuel pump, replaced it then the whistle was eliminated. Happened only when u accelerated (more when it was cold outside than when it was warm)...the minute you let off it would quit. Some food for thought...
 

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Had a the same problem in my 2000 Z3 mine ended up an accordian style intake tube that had a rip in it. If thats the case then air will start running into the throttle body and eventually dirt and grim will build up there and your gas mileage will turn to nothing.
 

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Very common problem on the X5........ I've replaced the accordian intake tube twice. I haven't seen it on the Z3.
 

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My 1.9 does the same thing. I get a whistle up front while accelerating at lower RPM's. Goes away above 2500 rpms or so. Doesn't do it when the car's just sitting there and revving.......thought it might be an intake leak, but since it doesn't happen when the car's just sitting, I'm wondering if it's just regular intake noise under load on this motor.
 

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Mine def was the intake tube, maybe when you drive the tranny torques just slightly causing the engine to torque etc...... just enough to separate the crack in the rubber bellows, especially with the intake under a vacuum......... At least that's what happened to the X5..... twice.
 

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I see no cracks in the accordian like tube or any other hoses. Weird, perhaps this is a normal noise on the Z4?? Runs like a dream!!
 

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I couldn't see the cracks either, but when I had the wife rev it up and I sqeezed the bellows...... she whistled...... errr the car that is. LOL After I got it off you could see the dry-rotted crack on on of the ribs that were molded into the bellows/tube, 2nd time I didn't even hesitate..... I changed it out and the cracks were in almost the same spot.
 

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XXXXXXXX
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Discussion Starter #11
I couldn't see the cracks either, but when I had the wife rev it up and I sqeezed the bellows...... she whistled...... errr the car that is. LOL After I got it off you could see the dry-rotted crack on on of the ribs that were molded into the bellows/tube, 2nd time I didn't even hesitate..... I changed it out and the cracks were in almost the same spot.
Yeah I am going to try it this weekend and see if its the tube.
 

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XXXXXXXX
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Discussion Starter #12
My 1.9 does the same thing. I get a whistle up front while accelerating at lower RPM's. Goes away above 2500 rpms or so. Doesn't do it when the car's just sitting there and revving.......thought it might be an intake leak, but since it doesn't happen when the car's just sitting, I'm wondering if it's just regular intake noise under load on this motor.
YEah mine is between just off idle to about 2500 also. You can very the whistle with playing with the throttle.
 
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