Squealing noise underneath the car

b-drizzle · 01-26-2024, 09:59 PM

2015 435x GC, making this squealing noise from under the car.

I've changed the belt tensioner pulley and bearing, removed Dinan intake and Dinan tuner. Today I replaced the Engine Block Breather Valve (PCV), used 1 minute gasket to seal it.

The noise is coming near the exhaust/cat/transfer case.. when i pull the engine oil cap it stops, car rough idles, then resumes when cap back on.

engine throws a code P0171 system too lean bank 1.

been chasing my tail.

View post on imgur.com

has anyone had similar experience? Any help would be tremendous!

thejeremyman9 · 01-27-2024, 02:59 PM

You mean you replaced the PCV part on the VC that isnt technically supposed to be replaced? Did you have the noise before that? Usually that squealing is a VC/PCV issue when it goes away when you remove the oil cap

rlesko · 01-27-2024, 09:31 PM

Valve cover 100%. Your quick fix didn’t work.

01-26-2024, 09:59 PM	#1
b-drizzle Private First Class 21 Rep 129 Posts Drives: 435i Gran Coupe xDrive Join Date: Jun 2014 Location: United States iTrader: (3)	Squealing noise underneath the car 2015 435x GC, making this squealing noise from under the car. I've changed the belt tensioner pulley and bearing, removed Dinan intake and Dinan tuner. Today I replaced the Engine Block Breather Valve (PCV), used 1 minute gasket to seal it. The noise is coming near the exhaust/cat/transfer case.. when i pull the engine oil cap it stops, car rough idles, then resumes when cap back on. engine throws a code P0171 system too lean bank 1. been chasing my tail. View post on imgur.com View post on imgur.com has anyone had similar experience? Any help would be tremendous!
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01-27-2024, 02:59 PM	#2
thejeremyman9 Major General 4362 Rep 7,602 Posts Drives: 2015 BMW 335i Join Date: May 2019 Location: Cali iTrader: (0)	You mean you replaced the PCV part on the VC that isnt technically supposed to be replaced? Did you have the noise before that? Usually that squealing is a VC/PCV issue when it goes away when you remove the oil cap
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01-27-2024, 09:31 PM	#3
rlesko Lieutenant 233 Rep 481 Posts Drives: F30 335i Join Date: Jan 2023 Location: New England iTrader: (1) Garage List 2012 335i [0.00]	Valve cover 100%. Your quick fix didn’t work.
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