Whistling Noise on rundown and at idle

1999 BMW 316
151,000 MILES • 4 CYL • 2WD • MANUAL
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STEVENMAC
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Hi.... I am experiencing a high pitched whistle in my 99 E46 BMW 316i 1.9. It happens once the car warms up after 20 miles or so.... It disappears if you fully press the accelerator but is louder as the car comes down to idle speed. Already changed the idle regulator at the advice of a shoddy mechanic who lied to me that he had fixed the problem. Please please please help... this noise is ruining my life... my vin is aw52308
Aug 31, 2008 at 10:34 AM
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DOCHAGERTY
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It sounds like you have a vacuum leak which will make that noise. Here is a guide to help you find it.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

It can be the crankcase ventilation system causing it as well.

Please run down this guide and report back

Cheers
Aug 31, 2008 at 12:04 PM
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HUSSAIN54
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hello, i am also experiencing the exact problem with my BMW 316. I have gone to three or four mechanics and everyone has diagnosed different problem. Kindly tell me how have u rectified it and what was the exact cause. Thanks
Jul 28, 2012 at 10:31 PM
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DOCHAGERTY
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11157501567 is the part you need, it is the crankcase vent valve #16 in the diagram below.

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Cheers
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Oct 26, 2012 at 6:27 AM