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TamimIqbal TamimIqbal is offline
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Default Loud Screech at High RPM Under Load? - 12-03-2021, 11:41 PM

Hi All,

Hoping I might be able to gain some insight here about a noise from my 2008 535xi wagon. When accelerating, there is a super loud screech that seems to be coming from the engine bay. Really sounds like tires breaking loose (itís that loud), but a stock xi isnít spinning the front tires (and the noise occurs in 4th gear at highway speeds as well). Starts after 5k rpm.

I installed a new belt + tensioner + pulleys earlier this year, but the noise was unchanged. I occasionally get a bit of a rattle from one of the accessories (likely the alternator) on cold-start, but it goes away within a minute. The screech doesnít sound like belt squeal though, and only happens under load.

Iím thinking it might be the PCV system, or maybe an exhaust leak. The car had new turbos 30k miles ago, but maybe something wasnít reassembled correctly? Seems too loud to be the PCV, but others may know better.
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THE BEAST THE BEAST is offline
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Default 12-06-2021, 11:44 PM

Quote:
Originally Posted by TamimIqbal
Hi All,

Hoping I might be able to gain some insight here about a noise from my 2008 535xi wagon. When accelerating, there is a super loud screech that seems to be coming from the engine bay. Really sounds like tires breaking loose (itís that loud), but a stock xi isnít spinning the front tires (and the noise occurs in 4th gear at highway speeds as well). Starts after 5k rpm.

I installed a new belt + tensioner + pulleys earlier this year, but the noise was unchanged. I occasionally get a bit of a rattle from one of the accessories (likely the alternator) on cold-start, but it goes away within a minute. The screech doesnít sound like belt squeal though, and only happens under load.

Iím thinking it might be the PCV system, or maybe an exhaust leak. The car had new turbos 30k miles ago, but maybe something wasnít reassembled correctly? Seems too loud to be the PCV, but others may know better.
You posted this before. With a youtube video attached.
Why ?
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