Chirping sound from under the hood

andy92782 · 04-27-2015, 07:21 PM

Wait for it..

It's not the belt or the tensioner pulley. Any ideas?

'08 328i.

JDane07 · 04-27-2015, 08:11 PM

Well that's a new sound to me. No trapped bird down there?

328i_E92_2007 · 04-27-2015, 09:05 PM

No idea, that's really strange. Subbed just to find out what it is. lol. Good luck!

mmmnot · 04-28-2015, 09:29 AM

Pulley? Tensionor? Any rattle or shifting on the belts whilst idling?

fravel · 04-28-2015, 09:36 AM

Is that the radiator fan kicking on that seems to coincide with the chirp starting? Maybe something is rubbing there, or you've got a nick in one of the fan blades causing a whistle when it spins?

andy92782 · 04-28-2015, 11:33 AM

Definitely not the tensioner pulley or the belt. Those were replaced and the noise remained.

I don't think it's the radiator fan because the sound is related to engine RPM. It may not be totally apparent in the audio but the noise comes and goes with RPM.

The other thing is that if the car is cruising you generally don't hear it but once you lift off the gas and start coasting the noise will show up. I had one person suggest it might be the vacuum pump which is driven off the timing chain.

bernard54321 · 04-28-2015, 01:52 PM

alternator? contacts worn down?

hongsc · 04-28-2015, 03:50 PM

No clue. Sounds like a Geiger Counter. Your car must have radiation?

04-27-2015, 07:21 PM	#1
andy92782 Private First Class 7 Rep 164 Posts Drives: '10 C2S, '04 4Runner 4x4 V8 Join Date: Feb 2007 Location: OC, CA iTrader: (0)	Chirping sound from under the hood Wait for it.. It's not the belt or the tensioner pulley. Any ideas? '08 328i.
	Appreciate 0 Tweet Quote

04-27-2015, 08:11 PM	#2
JDane07 Lieutenant Colonel 143 Rep 1,720 Posts Drives: 330i (sold), MK7 GTI Join Date: Nov 2011 Location: Napa, CA iTrader: (3)	Well that's a new sound to me. No trapped bird down there?
	Appreciate 0 Quote

04-27-2015, 09:05 PM	#3
328i_E92_2007 Private First Class 15 Rep 152 Posts Drives: 2007 328i Coupe Join Date: Jun 2014 Location: Los Angeles iTrader: (0) Garage List 2007 BMW 328i [9.00]	No idea, that's really strange. Subbed just to find out what it is. lol. Good luck!
	Appreciate 0 Quote

04-28-2015, 09:29 AM	#4
mmmnot Custom User Title 411 Rep 1,337 Posts Drives: E92 328i Join Date: Mar 2015 Location: Hotlanta iTrader: (2)	Pulley? Tensionor? Any rattle or shifting on the belts whilst idling? __________________ My "build" thread
	Appreciate 0 Quote

04-28-2015, 09:36 AM	#5
fravel Colonel 1648 Rep 2,494 Posts Drives: Monaco Blue '06 330i Join Date: Aug 2012 Location: The Nasti 'Nati iTrader: (1)	Is that the radiator fan kicking on that seems to coincide with the chirp starting? Maybe something is rubbing there, or you've got a nick in one of the fan blades causing a whistle when it spins? __________________
	Appreciate 0 Quote

04-28-2015, 11:33 AM	#6
andy92782 Private First Class 7 Rep 164 Posts Drives: '10 C2S, '04 4Runner 4x4 V8 Join Date: Feb 2007 Location: OC, CA iTrader: (0)	Definitely not the tensioner pulley or the belt. Those were replaced and the noise remained. I don't think it's the radiator fan because the sound is related to engine RPM. It may not be totally apparent in the audio but the noise comes and goes with RPM. The other thing is that if the car is cruising you generally don't hear it but once you lift off the gas and start coasting the noise will show up. I had one person suggest it might be the vacuum pump which is driven off the timing chain.
	Appreciate 0 Quote

04-28-2015, 01:52 PM	#7
bernard54321 Lieutenant 56 Rep 474 Posts Drives: 2009 328I E90 Join Date: Dec 2012 Location: l.a. california iTrader: (1) Garage List 2006 Bmw 330i [0.00] 2009 328I E90 [0.00]	alternator? contacts worn down? __________________ //// M3 Conversion front bumper //// Csl trunk lid //// mtech rear bumper //// resonator delete //// airrex digital air suspension //// megan camber arms //// godspeed toe arms //// Stance Wheels sf01 19x8.5 / 19x9.5 //// instagram: thebernardexperience
	Appreciate 0 Quote

04-28-2015, 03:50 PM	#8
hongsc Captain 153 Rep 982 Posts Drives: 2011 BMW 328i Join Date: Jul 2013 Location: Amazon Prime iTrader: (1)	No clue. Sounds like a Geiger Counter. Your car must have radiation? __________________ 2011 BMW 328i Space Grey\|18" Avant Garde m359\|Michelin Pilot Sport A/S2\|Eibach Pro-Kit Springs\|Koni FSD\|M3 U+L Control Arms\|Lux Angel Eyes\|Stoptech\|Hawk 5.0\|aFe Race Pipes\|BMW PE
	Appreciate 0 Quote