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Thunderguts · 03-06-2020, 10:40 AM

It definitely doesn't sound normal to me. I assume the pitch changes with RPM. I would try to narrow it down to inside the engine or an accessory. Some possible guesses: belt tensioner or PS pump.

03-06-2020, 10:40 AM	#3
Thunderguts Major 794 Rep 1,006 Posts Drives: 2009 128i Sport MT Join Date: Jul 2018 Location: DFW iTrader: (0)	It definitely doesn't sound normal to me. I assume the pitch changes with RPM. I would try to narrow it down to inside the engine or an accessory. Some possible guesses: belt tensioner or PS pump.
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