Whistling noise from engine bay

NikhilJ · 03-12-2015, 08:43 PM

Hi all,

I have this very annoying problem. Under acceleration around 2000 rpm, the car makes a whistling noise. This sound is loud on cold days and not so much on warm or have been driven for 30 mins or so.

Also, I have to top off oil every 700-800 miles. Not sure if these are related or not.

Spoke to the dealer and got the standard answer, its turbo spooling.

Has someone experienced the same problem?
Please help!! Its really annoying and have been struggling to find a fix for last 18 months.

Its 2007 335i with close to 78k miles.

thanks.

woggledog · 03-13-2015, 04:25 AM

As you have a turbo, this is the turbo PULLING air into the air intake, and is normal. HOWEVER, you may have a small boost leak somewhere. It is possible to get smoke bombs especially for this purpose to find out where the leak is. With the EGR blocked off (The last component before the Inlet manifold), a small smoke bomb is placed into the pipes, blocked off, and then external pressure applied, forcing the smoke out of any weak points. If you've had a Golf MkIV TDI, you'd have gone through this at least once in your car's lifetime.

If it's a whine, not a whistle, then I'd get your turbo looked at quickly.

Actually, if you're going through oil that quickly, I would look at getting a look at your turbo.

NikhilJ · 03-13-2015, 10:21 AM

Thanks woggledog.

I am not an expert but could you explain how oil and turbos are related?

03-12-2015, 08:43 PM	#1
NikhilJ Registered 0 Rep 2 Posts Drives: 335i 2007 Join Date: Jan 2014 Location: United States iTrader: (0)	Whistling noise from engine bay Hi all, I have this very annoying problem. Under acceleration around 2000 rpm, the car makes a whistling noise. This sound is loud on cold days and not so much on warm or have been driven for 30 mins or so. Also, I have to top off oil every 700-800 miles. Not sure if these are related or not. Spoke to the dealer and got the standard answer, its turbo spooling. Has someone experienced the same problem? Please help!! Its really annoying and have been struggling to find a fix for last 18 months. Its 2007 335i with close to 78k miles. thanks.
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03-13-2015, 04:25 AM	#2
woggledog First Lieutenant 28 Rep 321 Posts Drives: 2015 F31 320D Sport Join Date: Jan 2014 Location: Surrey iTrader: (0)	As you have a turbo, this is the turbo PULLING air into the air intake, and is normal. HOWEVER, you may have a small boost leak somewhere. It is possible to get smoke bombs especially for this purpose to find out where the leak is. With the EGR blocked off (The last component before the Inlet manifold), a small smoke bomb is placed into the pipes, blocked off, and then external pressure applied, forcing the smoke out of any weak points. If you've had a Golf MkIV TDI, you'd have gone through this at least once in your car's lifetime. If it's a whine, not a whistle, then I'd get your turbo looked at quickly. Actually, if you're going through oil that quickly, I would look at getting a look at your turbo.
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03-13-2015, 10:21 AM	#3
NikhilJ Registered 0 Rep 2 Posts Drives: 335i 2007 Join Date: Jan 2014 Location: United States iTrader: (0)	Thanks woggledog. I am not an expert but could you explain how oil and turbos are related?
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