help with an X5 Diesel engine noise

Dr. Anthony · 10-11-2015, 08:30 PM

Hi guys,

I have a 2009 X5 diesel and I'm trying to diagnose a noise. It sounds like a screeching.. loud scream. I've posted a video and was wondering if someone has heard this before. I've been searching all week and have yet to find something similar. Sorry for the poor quality video, but it's all I could come up with.

any help is greatly appreciated.
the engine light is related to nox sensor replacement.
currently have 210,000 km (130k miles)
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CrashRat · 10-16-2015, 11:25 AM

Hi Dr. Anthony, the noise I'm hearing is sounding like you might have a vacuum leak. Are you noticing any loss of power too? Can you plug on a vacuum gauge and see what it does when that noise happens?

A visual inspection of all the vacuum/boost lines might lead to something. You could also try squirting a little bit of soapy water around all the vacuum connections. if the pitch changes or it goes away altogether, you've found your problem.

I can't tell for sure from the video if it's a vacuum or boost leak though. Just has that kind of sound to it.

Good luck.

Greg

Dr. Anthony · 10-16-2015, 12:04 PM

Quote:

Originally Posted by CrashRat

Hi Dr. Anthony, the noise I'm hearing is sounding like you might have a vacuum leak. Are you noticing any loss of power too? Can you plug on a vacuum gauge and see what it does when that noise happens?

A visual inspection of all the vacuum/boost lines might lead to something. You could also try squirting a little bit of soapy water around all the vacuum connections. if the pitch changes or it goes away altogether, you've found your problem.

I can't tell for sure from the video if it's a vacuum or boost leak though. Just has that kind of sound to it.

Good luck.

Greg

Thanks for the info,
I brought it by my friend's shop. We took it for a test drive. It was hard to replicate. (of course) However, we did a bit of a stress test by holding the brake and trying to build some boost stationary. (yep, I know this is hard on the transmission) From that (also had 2 techs listen for it) it sounds like a boost leak somewhere.

We did notice some soot buildup around the bypass valve, and also some soot where the pipe goes into the throttle valve/egr area.

But yes, I now think its boost/vacuum related. I'll fog the motor and see where I find leaks.

CrashRat · 10-16-2015, 08:09 PM

Excellent. Sounds like you're very much on the right track. If your friend has an OBDII scanner, you can often get some clue as to where the leak might be by checking DTC codes and watching boost in real time if his reader is sophisticated enough. I come from the VW world where I had the factory VAG-COM software and USB-to-OBDII cable that would let me measure and graph anything I wanted. Too new to BMW's to know yet if anything like that exists here outside of what the dealer/indy service centers have access to?

Given the sharpness of the noise though, I would expect to find something fairly near one of the turbo outlets such as the bypass valve you mentioned. I've also seen the hose clamps cut into the rubber hoses over time, resulting in leaks. Boost leaks can be a bit of a pain to track down though so I hope it turns out to be an easy one for you.

btw, since you mention having 130k on your rig - how would you say it's been for reliability? I just got mine Sunday and expect to drive it well into the 6 figures too.

10-11-2015, 08:30 PM	#1
Dr. Anthony Lieutenant 56 Rep 451 Posts Drives: e46 m3, e30 s52 318is, F15d Join Date: Aug 2009 Location: Edmonton iTrader: (6)	help with an X5 Diesel engine noise Hi guys, I have a 2009 X5 diesel and I'm trying to diagnose a noise. It sounds like a screeching.. loud scream. I've posted a video and was wondering if someone has heard this before. I've been searching all week and have yet to find something similar. Sorry for the poor quality video, but it's all I could come up with. any help is greatly appreciated. the engine light is related to nox sensor replacement. currently have 210,000 km (130k miles) [u2b] [/u2b]
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10-16-2015, 11:25 AM	#2
CrashRat Private 17 Rep 53 Posts Drives: 2011 X5 35d Join Date: Oct 2015 Location: Portland, OR iTrader: (0)	Hi Dr. Anthony, the noise I'm hearing is sounding like you might have a vacuum leak. Are you noticing any loss of power too? Can you plug on a vacuum gauge and see what it does when that noise happens? A visual inspection of all the vacuum/boost lines might lead to something. You could also try squirting a little bit of soapy water around all the vacuum connections. if the pitch changes or it goes away altogether, you've found your problem. I can't tell for sure from the video if it's a vacuum or boost leak though. Just has that kind of sound to it. Good luck. Greg
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10-16-2015, 08:09 PM	#4
CrashRat Private 17 Rep 53 Posts Drives: 2011 X5 35d Join Date: Oct 2015 Location: Portland, OR iTrader: (0)	Excellent. Sounds like you're very much on the right track. If your friend has an OBDII scanner, you can often get some clue as to where the leak might be by checking DTC codes and watching boost in real time if his reader is sophisticated enough. I come from the VW world where I had the factory VAG-COM software and USB-to-OBDII cable that would let me measure and graph anything I wanted. Too new to BMW's to know yet if anything like that exists here outside of what the dealer/indy service centers have access to? Given the sharpness of the noise though, I would expect to find something fairly near one of the turbo outlets such as the bypass valve you mentioned. I've also seen the hose clamps cut into the rubber hoses over time, resulting in leaks. Boost leaks can be a bit of a pain to track down though so I hope it turns out to be an easy one for you. btw, since you mention having 130k on your rig - how would you say it's been for reliability? I just got mine Sunday and expect to drive it well into the 6 figures too.
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