Whats the noise & is my car going to blowup?

Martyn76 · 03-17-2016, 10:18 AM

Hi All

I've had my 06 E91 330 auto for approx. 1.5yrs now and not had any problems with it aside from service items, I've started to notice a noise which is something between a whine and whistle when under light throttle (moving away from a stand still for example), it may have been there all this time but I've started to pay more attention to it recently.

It picks up pitch as more throttle is applied but then seems to disappear once at speed, 30mph +, I've not notice any performance issues so not sure what it is.

So my question is, what it is and is it terminal? I have images of the turbo letting go or something similarly catastrophic.

The way my luck is at the moment , it'll end up costing me money

...

Thanks in advance

Rudz · 03-17-2016, 10:31 AM

Turbo is my guess, get it checked

stampylove · 03-17-2016, 02:24 PM

Pop the bonnet locate the turbo and get a pal to rev the engine you'll have a better chance of diagnosing.
Good luck.

Martyn76 · 03-22-2016, 05:45 AM

Cheers guys, will have a listen and see if I can locate it.

Aragorn30d · 03-22-2016, 07:23 AM

My turbo whines when cold. Sounds a bit like a police siern in the distance if you modulate the throttle a bit. Like you say, its fairly subtle and not always noticable, colder weather makes it more noticable. Goes away (or at least i stop noticing it!) when the engine is warm.

Its not unusual, the brand new Alpina turbo my brother fitted to his 320d made the same noise from the moment it was fitted, and isnt a sign of impending doom unless it starts getting worse.

Martyn76 · 03-22-2016, 08:40 AM

Quote:

Originally Posted by Aragorn30d

My turbo whines when cold. Sounds a bit like a police siern in the distance if you modulate the throttle a bit. Like you say, its fairly subtle and not always noticable, colder weather makes it more noticable. Goes away (or at least i stop noticing it!) when the engine is warm.

Its not unusual, the brand new Alpina turbo my brother fitted to his 320d made the same noise from the moment it was fitted, and isnt a sign of impending doom unless it starts getting worse.

This is exactly what mine sounds like, very much attached to throttle movement, glad to hear it's not something terminal.

abeardo83 · 03-22-2016, 08:41 AM

could also be a leaky vac / boost pipe?

Martyn76 · 03-22-2016, 09:51 AM

Quote:

Originally Posted by abeardo83

could also be a leaky vac / boost pipe?

I was wondering that after the first couple of comments, it's been there since I bought the car approx. 18 months ago, so not really sure if there has been any performance gain, it has been into BMW for various service items and nothing was highlighted on the health check (of course that doesn't mean there isn't something amiss).

Digitalize · 03-22-2016, 11:35 AM

It could also be the clutch on the alternator/waterpump belt. Mine did this, sounded very similar to what I'd expect a noisy turbo to sound like (which is usually caused by a slightly damaged fin).

My diff also whines when cold which produces a similar sound. Not as easy in an auto but if it's related to engine speed it's more likely turbo/belt clutch, and if it's wheel speed it's pretty much diff.

Aragorn30d · 03-22-2016, 11:50 AM

Mines related to engine load rather than speed. Manual box on mine so you can apply load without the revs changing much etc, letting you hear the noise. So its almost certainly the turbo.

Like you say its often caused by damage, but very odd that it goes away when warm! If it was damage it'd throw the shaft out of balance and it probably wouldnt last very long at all, whereas both mine and the OP's has had the noise for a while.

The wifes car had a similar sound that was getting worse and worse over a period of about 6 months until it sounded so bad that it was there almost all the time and i replaced the turbo. On inspection there was some witness marks in the turbine housing where the turbine wheel had been contacting against the housing, it looked like the housing had cracked, and the high spot caused by the crack was enough to just touch the wheel.

Perhaps its something similar, and the thermal expansion when hot sorts out the clearnaces? It could even be touching carbon deposits rather than a cracked housing?

Digitalize · 03-22-2016, 12:13 PM

can be the tiniest nick on one of the blades which would then create a noise.

Without individually listening to one/the other you can't say whether it is turbo/belt clutch as they are both directly linked to engine RPM. Turbo is on the left front of the engine, clutch is on the front right.

03-17-2016, 10:18 AM	#1
Martyn76 Private 12 Rep 66 Posts Drives: LeMans Blue E91 330D Join Date: Nov 2015 Location: Corby, Northants iTrader: (0)	Whats the noise & is my car going to blowup? Hi All I've had my 06 E91 330 auto for approx. 1.5yrs now and not had any problems with it aside from service items, I've started to notice a noise which is something between a whine and whistle when under light throttle (moving away from a stand still for example), it may have been there all this time but I've started to pay more attention to it recently. It picks up pitch as more throttle is applied but then seems to disappear once at speed, 30mph +, I've not notice any performance issues so not sure what it is. So my question is, what it is and is it terminal? I have images of the turbo letting go or something similarly catastrophic. The way my luck is at the moment , it'll end up costing me money... Thanks in advance Last edited by Martyn76; 03-17-2016 at 01:12 PM..
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03-17-2016, 10:31 AM	#2
Rudz Lieutenant Colonel 236 Rep 1,720 Posts Drives: F30 335D xDrive Shadow Edition Join Date: Feb 2012 Location: UK iTrader: (3)	Turbo is my guess, get it checked
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03-17-2016, 02:24 PM	#3
stampylove Private First Class 18 Rep 123 Posts Drives: E91 325d lci 2010 Join Date: Jan 2016 Location: Manchester iTrader: (0)	Pop the bonnet locate the turbo and get a pal to rev the engine you'll have a better chance of diagnosing. Good luck.
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03-22-2016, 05:45 AM	#4
Martyn76 Private 12 Rep 66 Posts Drives: LeMans Blue E91 330D Join Date: Nov 2015 Location: Corby, Northants iTrader: (0)	Cheers guys, will have a listen and see if I can locate it.
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03-22-2016, 07:23 AM	#5
Aragorn30d Lieutenant Colonel 169 Rep 1,596 Posts Drives: E90 330d Join Date: Mar 2015 Location: Fife iTrader: (0)	My turbo whines when cold. Sounds a bit like a police siern in the distance if you modulate the throttle a bit. Like you say, its fairly subtle and not always noticable, colder weather makes it more noticable. Goes away (or at least i stop noticing it!) when the engine is warm. Its not unusual, the brand new Alpina turbo my brother fitted to his 320d made the same noise from the moment it was fitted, and isnt a sign of impending doom unless it starts getting worse.
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03-22-2016, 08:41 AM	#7
abeardo83 Captain 97 Rep 808 Posts Drives: E92 M3 Join Date: Nov 2015 Location: Cheshire iTrader: (2) Garage List 2008 BMW M3 [0.00]	could also be a leaky vac / boost pipe?
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03-22-2016, 11:35 AM	#9
Digitalize Photographer 407 Rep 2,635 Posts Drives: 320D Join Date: Jun 2013 Location: UK iTrader: (0)	It could also be the clutch on the alternator/waterpump belt. Mine did this, sounded very similar to what I'd expect a noisy turbo to sound like (which is usually caused by a slightly damaged fin). My diff also whines when cold which produces a similar sound. Not as easy in an auto but if it's related to engine speed it's more likely turbo/belt clutch, and if it's wheel speed it's pretty much diff.
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03-22-2016, 11:50 AM	#10
Aragorn30d Lieutenant Colonel 169 Rep 1,596 Posts Drives: E90 330d Join Date: Mar 2015 Location: Fife iTrader: (0)	Mines related to engine load rather than speed. Manual box on mine so you can apply load without the revs changing much etc, letting you hear the noise. So its almost certainly the turbo. Like you say its often caused by damage, but very odd that it goes away when warm! If it was damage it'd throw the shaft out of balance and it probably wouldnt last very long at all, whereas both mine and the OP's has had the noise for a while. The wifes car had a similar sound that was getting worse and worse over a period of about 6 months until it sounded so bad that it was there almost all the time and i replaced the turbo. On inspection there was some witness marks in the turbine housing where the turbine wheel had been contacting against the housing, it looked like the housing had cracked, and the high spot caused by the crack was enough to just touch the wheel. Perhaps its something similar, and the thermal expansion when hot sorts out the clearnaces? It could even be touching carbon deposits rather than a cracked housing?
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03-22-2016, 12:13 PM	#11
Digitalize Photographer 407 Rep 2,635 Posts Drives: 320D Join Date: Jun 2013 Location: UK iTrader: (0)	can be the tiniest nick on one of the blades which would then create a noise. Without individually listening to one/the other you can't say whether it is turbo/belt clutch as they are both directly linked to engine RPM. Turbo is on the left front of the engine, clutch is on the front right.
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