# strange acceleration noise, possible boost leak? not diverter valve...



## freezermink (Dec 17, 2002)

as posted on the mkV jetta/golf forum, but i think this forum would be of better assistance... seems that two of us are having the same problem... 

_Quote, originally posted by *BradNBerkeley* »_I've had my GTI for a little over a month (over 1,000 miles) and all of a sudden last night, it started making a strange "whoosh" noise under acceleration. It sounds like it's coming from under the hood on the driver's side. It's like a rush of air, almost as if it were part of the ventilation system. It sounds like when I has a cold air intake on a Sentra SE-R many years ago, that kind of breathing noise. It seems that the car has lost some power too, but that might be just in my head. Here's what I've done so far:
* Turn off HVAC - sound still present.
* Rev the engine when in neutral - sound NOT present.
* Tried it in all gears - sound is present in all gears under acceleration.
* Sound is NOT present at speed when not accelerating, only under acceleration.
Thanks for anyone's help.


and then my post:

_Quote, originally posted by *freezermink* »_i have the EXACT same problem. 
it showed up after a brief bout with a freak snow fall and a little encounter with the corner of a fence at 10 mph. i need a new bumper obviously, and a fog light housing, but other than that i was pretty lucky. however, the next morning driving to work i'm hearing the same thing you're describing. only under acceleration, under load, it sounds like the defroster turned up like crazy. its obviously a boost leak somewhere, but for the last couple days we haven't been able to locate it. our guess is that the accident cracked an intercooler pipe/fitting or something of the like and that the crack is closed up until under pressure. keep my updated and i'll do the same once we find out whats goin on. http://****************.com/smile/emthup.gif 

just today we checked the diverter valve and it is in perfect condition as well as the engine cover. anybody?


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## jasontrb (Apr 13, 2006)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (freezermink)*

The sound you are hearing might be the sound of the air intake sucking air. It can be heard with a stock intake but very softly. But very noticable sometimes to the level of annorying to some people if you have changed to a high flow intake. My Ottenger intake doesn't make that much of noise since it uses the stock air box(engine cover), so is the carbonio(the same thing i guess).


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## freezermink (Dec 17, 2002)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (jasontrb)*


_Quote, originally posted by *jasontrb* »_The sound you are hearing might be the sound of the air intake sucking air. It can be heard with a stock intake but very softly. But very noticable sometimes to the level of annorying to some people if you have changed to a high flow intake. My Ottenger intake doesn't make that much of noise since it uses the stock air box(engine cover), so is the carbonio(the same thing i guess).









kind of... 
i should specify that i have a stock intake etc that is working normally, i have 20k miles on the car and have not heard this noise until this past week. i'm pretty anal about phantom noises in the car, and i'm pretty sure this wasn't there before. its quite noticeable, so i doubt its just the intake... argh.


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## digitalhippie (Apr 21, 2004)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (freezermink)*

do you have a boost gauge? have you noticed any loss of power, fuel efficiency, or boost?


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## GolfRS (Feb 4, 2006)

try changing your N75
i kinda had a similar problem


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## Rub-ISH (Aug 8, 2006)

*Re: (GolfRS)*

PVC valve failure most likely. Those are the symptoms i had when my car was still stock and had boost loss through the oil cap


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## freezermink (Dec 17, 2002)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (digitalhippie)*


_Quote, originally posted by *digitalhippie* »_do you have a boost gauge? have you noticed any loss of power, fuel efficiency, or boost?

nope, still working on grabbing a boost gauge. i haven't seen any loss in fuel efficiency though. 
we checked the pcv quickly, but didn't see anything wrong upon first inspection...


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## digitalhippie (Apr 21, 2004)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (freezermink)*


_Quote, originally posted by *freezermink* »_we checked the pcv quickly, but didn't see anything wrong upon first inspection... 

When my PCV failed, it made an odd noise under acceleration. But, from visual inspection, its hard to see the failure. The only visual sign is when the oil finally starts blowing out the oil fill cap. For me, that didn't happen until the boost had dropped off steadliy for a bit (from 21 down to 15... when it got around 15 there was enough venting into the valve cover to blow oil out).


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## freezermink (Dec 17, 2002)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (digitalhippie)*


_Quote, originally posted by *digitalhippie* »_
When my PCV failed, it made an odd noise under acceleration. But, from visual inspection, its hard to see the failure. The only visual sign is when the oil finally starts blowing out the oil fill cap. For me, that didn't happen until the boost had dropped off steadliy for a bit (from 21 down to 15... when it got around 15 there was enough venting into the valve cover to blow oil out).

hmm... i guess we'll have to take the damn engine cover off again. heh. we had it off a couple times yesterday and there is no oil blowby that i can see anywhere on the fill cap or otherwise. damnit. 
the other original poster above is got the car at a dealership at the moment (or so i hope), so it shouldn't be too long, but damnit its driving me crazy.


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## madfella (Oct 6, 2005)

*Re: (GolfRS)*


_Quote, originally posted by *GolfRS* »_try changing your N75
i kinda had a similar problem

Wastegate bypass?? I don't really think so.


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## BradNBerkeley (Jul 2, 2002)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (freezermink)*

Here's what happened in my case (I had the same problem):

_Quote, originally posted by *BradNBerkeley* »_Update from the dealer today: they claim that the intercooler is busted. They say that it was pushed up from beneath and broken, and want to charge me $900 to replace. I haven't taken it off of city streets since I bought the thing, so I'm not sure that I believe them. I'm going to go take a look tomorrow. Grr...











_Modified by BradNBerkeley at 5:54 PM 12-6-2006_


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## freezermink (Dec 17, 2002)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (BradNBerkeley)*

total crap. i'm having an adjuster come look at it tomorrow for all the other accident damage anyway, maybe between the shop its at and the adjuster we can figure out whats going on.


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## BradNBerkeley (Jul 2, 2002)

*Re: strange acceleration noise, possible boost leak? not diverter valve... (freezermink)*

I saw my car at the dealer today. There is a tiny scrape under the front bumper on the black plastic lip. It's no different than what most cars get every day pulling into driveways or going over too-large speed bumps. It's not a dent, it's a minor scratch.
Note that the bottom of the radiator and intercooler assembly (they're kind of a sandwich in front of the fans) sits IMMEDIATELY above the plastic bumper lip. There's not even a gap, so no protection from a bump, pothole, ground, etc. It seems really flimsy.
Anyhow, the dealer says that this caused the radiator and intercooler to be shoved up, causing the intercooler to break somewhere and hence I'm losing boost. I disagreed and have called VWoA to complain.


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## C_Nigel (Dec 8, 2006)

Hi guys,
Care to share a bit more of this sound? How does it sound like?
I have a sound problem in my GTI during acceleration too... the sound occasionally occurs when the car is at abt 50kmh and gear is changing from 4th to 5th or 5th to 6th... the sound will occur at the point of gear change.. 
Another unique thing that i have noted is that the road must be curving left or at a certain inclination for the sound to happen..
It sounds like a short blast of air escaping... only last a split second....
This is really giving a lot of headache now...
Cheers!


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## BradNBerkeley (Jul 2, 2002)

*Re: (C_Nigel)*


_Quote, originally posted by *C_Nigel* »_
Care to share a bit more of this sound? How does it sound like?
I have a sound problem in my GTI during acceleration too... the sound occasionally occurs when the car is at abt 50kmh and gear is changing from 4th to 5th or 5th to 6th... the sound will occur at the point of gear change.. 


Hi - When it was happening to me it was because of loss of pressure. It happened in every gear and every situation where the turbo spooled. Yours sounds different, but I'm not a mechanic so I don't know what to tell you.


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## freezermink (Dec 17, 2002)

*Re: (BradNBerkeley)*


_Quote, originally posted by *BradNBerkeley* »_
Hi - When it was happening to me it was because of loss of pressure. It happened in every gear and every situation where the turbo spooled. Yours sounds different, but I'm not a mechanic so I don't know what to tell you.

update:
we took the front bumper off to find some of what we had expected... the lower intercooler/radiator mount broken. but also that breaking, the upper drivers side intercooler mount also broke. no big deal, except that the mount is hollow and with that breaking created a quarter sized hole for all my boost to leak through. d'oh. glad we have that figured out now. looks like insurance money = body work AND front mount.


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## BradNBerkeley (Jul 2, 2002)

*Re: (freezermink)*


_Quote, originally posted by *freezermink* »_
we took the front bumper off to find some of what we had expected... the lower intercooler/radiator mount broken. but also that breaking, the upper drivers side intercooler mount also broke. no big deal, except that the mount is hollow and with that breaking created a quarter sized hole for all my boost to leak through. d'oh. glad we have that figured out now. looks like insurance money = body work AND front mount. 

That must be what happened to my car, too. The lower mount broke and sagged just a bit, but the leak was from the upper driver's side of the radiator / intercooler assembly. There is absolutely no visual sign of a break, just a leak. That's lame, poorly designed IMO. We should watch this carefully over the next year, I bet there will be lots of others with this problem.


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## BradNBerkeley (Jul 2, 2002)

*Re: (freezermink)*


_Quote, originally posted by *freezermink* »_no big deal, except that the mount is hollow and with that breaking created a quarter sized hole for all my boost to leak through.

Freezermink, were you able to snap any pictures of this?


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## freezermink (Dec 17, 2002)

*Re: (BradNBerkeley)*


_Quote, originally posted by *BradNBerkeley* »_
Freezermink, were you able to snap any pictures of this?

yep. lots. gimme a couple and i'll have'em up.


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## freezermink (Dec 17, 2002)

*Re: (freezermink)*

ok, so you can see here that the intercooler/radiator etc is crooked as hell. the next 2 pictures show the underside and the assembly mount that has been pretty much f'ed. (not to mention a cracked to hell fender liner etc.) 



the orange arrow indicates the side of the intercooler that the hoses mount to at the bottom that continues up to the top and has a tab that slides into a top intercooler mount, which is the piece that snapped off creating a quarter sized boost leak. great. 


the broken piece you see inside the yellowish surround is part of the intercooler which snapped and stayed inside the mount. the cooresponding hole is where the leak is. time for a new intercooler. yay.















here's an outside shot of the carnage: 



_Modified by freezermink at 7:45 PM 12-13-2006_


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## britGTIflav (Oct 21, 2003)

are you trying to contact VWoA about fixing that? i cant blame the dealer for charging you (if you are the person who said that)
But i have this noise too, under load, typically in a higher gear where the turbo can have some substantial boost. i have owned a turbo before, the noise doesnt sound like the turbo spooling...the noise sounds like air is just rushing through something. it is difficult to explain.


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## BradNBerkeley (Jul 2, 2002)

*Re: (britGTIflav)*


_Quote, originally posted by *britGTIflav* »_
But i have this noise too, under load, typically in a higher gear where the turbo can have some substantial boost. i have owned a turbo before, the noise doesnt sound like the turbo spooling...the noise sounds like air is just rushing through something. it is difficult to explain. 

That's exactly what mine sounded like and I think Freezermink's sounded the same. It's air rushing, not a spooling sound (never really heard spooling in my GTI with the 2.0 FSI, but I used to be able to hear my 1.8T spool). It's possible you have a similar situation.


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## BradNBerkeley (Jul 2, 2002)

*Re: (freezermink)*


_Quote, originally posted by *freezermink* »_
the broken piece you see inside the yellowish surround is part of the intercooler which snapped and stayed inside the mount. the cooresponding hole is where the leak is. time for a new intercooler. yay.

















Great pics, thanks! Sorry that happened to your car, that's a bummer.
The hollow intercooler piece staying inside of the mount, though, looks like a serious design flaw. I think that there will be many, many more of these broken intercoolers (which, in reality, are just broken mounts). Here's a pic of my car with broken intercooler, and as you can see there's no visible damage (it supposedly happened because something pushed up the bumper from below).
http://photos.bradandrews.info...10734
I asked the repair shop to keep the broken intercooler, so I'll try to post pics once I get it.


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## britGTIflav (Oct 21, 2003)

*Re: (BradNBerkeley)*


_Quote, originally posted by *BradNBerkeley* »_
That's exactly what mine sounded like and I think Freezermink's sounded the same. It's air rushing, not a spooling sound (never really heard spooling in my GTI with the 2.0 FSI, but I used to be able to hear my 1.8T spool). It's possible you have a similar situation.

Do you have an aftermarket, stiffer suspension by any chance??


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## BradNBerkeley (Jul 2, 2002)

*Re: (britGTIflav)*


_Quote, originally posted by *britGTIflav* »_Do you have an aftermarket, stiffer suspension by any chance?? 

Nope, stock. Here are (finally) some pics of my intercooler. One side is broken, the other is not. These two little pegs hold up the entire radiator, fan, and intercooler assembly! This was a $600 repair at my shop, $900 at the dealer.

























_Modified by BradNBerkeley at 4:39 PM 2-20-2007_


_Modified by BradNBerkeley at 4:40 PM 2-20-2007_


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## ssaffioti (Apr 9, 2006)

*Re: (C_Nigel)*


_Quote, originally posted by *C_Nigel* »_I have a sound problem in my GTI during acceleration too... the sound occasionally occurs when the car is at abt 50kmh and gear is changing from 4th to 5th or 5th to 6th... the sound will occur at the point of gear change.. 
It sounds like a short blast of air escaping... only last a split second....
This is really giving a lot of headache now...

I think *this* particular noise is normal operation of the DV. I found this video on Youtube (I think it's a vortex member) of a GTI with an Injen intake. You can hear the DV:
http://www.youtube.com/watch?v=hKTvmO7bTzI



_Modified by ssaffioti at 5:08 PM 2-20-2007_


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## notahonda (Jul 18, 2006)

Wow I just lost all confidence in the stock intercooler. I had heard how efficient it was but didnt realize its plastic and supports all that stuff. I do see why it works so well. Thats a ton of surface area. Front mount here I come. At least aluminum bends not breaks ok welds can but in general bends.


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## shue333 (Feb 19, 2007)

*Re: (notahonda)*

ALL confidence? wow......


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## freezermink (Dec 17, 2002)

*Re: (BradNBerkeley)*


_Quote, originally posted by *BradNBerkeley* »_









that is EXACTLY what happened to mine. losing all confidence in the stock intercooler is a bit too far, however, considering at least one of us was in a minor accident that caused the radiator support and intercooler to be pushed up breaking the tabs. eh. i'm finally getting it all back together on the 5th of march. should be good as new, with a few body-kit type goodies of course.


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## BradNBerkeley (Jul 2, 2002)

*Re: (freezermink)*


_Quote, originally posted by *freezermink* »_that is EXACTLY what happened to mine. losing all confidence in the stock intercooler is a bit too far, however, considering at least one of us was in a minor accident that caused the radiator support and intercooler to be pushed up breaking the tabs. eh. i'm finally getting it all back together on the 5th of march. should be good as new, with a few body-kit type goodies of course.









I think that the intercooler is fine, it's the wimpy plastic support pegs (that cause a gaping pressure loss when broken!) that's a Bad Engineering Idea in my opinion.
Glad that you'll be back soon, freezermink.


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## dubbkidd (Mar 10, 2006)

*Re: (BradNBerkeley)*

is it more of a woshing sound, or does it sound like the turbo is whining? because i has a problem where my car would make a whining noise every now and then, but would only make about 8psi of boost..and my diverter valve wasnt ripped


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## freezermink (Dec 17, 2002)

*Re: (dubbkidd)*


_Quote, originally posted by *BradNBerkeley* »_
I think that the intercooler is fine, it's the wimpy plastic support pegs (that cause a gaping pressure loss when broken!) that's a Bad Engineering Idea in my opinion.
Glad that you'll be back soon, freezermink.

agreed. the design in integrating the tabs on the sides leading into the intercooler itself was retarded. someone was at the bottom of a bottle of jagr when they did that. 

_Quote, originally posted by *dubbkidd* »_is it more of a woshing sound, or does it sound like the turbo is whining? because i has a problem where my car would make a whining noise every now and then, but would only make about 8psi of boost..and my diverter valve wasnt ripped

nope, just 'wooshing'. whining sounds like a different, more serious problem, but i dunno. the sound i hear is straight boost leak, rushing air etc.


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## Syafiqsheafi (May 24, 2018)

https://youtu.be/HS1gcFmZ5R8


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