Possible leak somewhere...Update- Leak found...now to FIX

[Stompie]

hozit guys,

hope this is in the correct section.

last year about September my polo started making some hissing sounds, almost sounds like a leaking exhaust.

i went and checked the exhaust but no leaks, ran logs and no boost leaks as ECU is getting the requested boost. changed DP as i thought it could maybe be the De-cat i was running or the gasket between the DP and Turbo. but still this hissing leaking noise is there.

this noise comes in when you rev the car, or start driving...

could this be the symptoms of a cracked manifold? i still have all my power and the sound doesn't seem to get louder?

seriously need to get rid of this sound....its irritating!!

[Amith11]

At the risk of me sounding dumb...

Is it not just your D/V ?

[Stompie]

lol im open for any sugestions.

why would you say DV? i mean this hissing starts happening from pull away through revs, at low revs there isnt any boost so the boost can open it...ive changed springs as well. new TIP was installed to make sure its not a leak.

the only thing i havent checked is the manifold, mani gasket, mani to turbo gasket...

[Tdi jetta 4 ever]

Does this happen when the aircon is on or off?

[Stompie]

haven't really checked it that way but air-con is mostly off...

[ruler_70]

I had a similar sound coming from my engine bay and it turned out it was my engine cover that had come loose and was rattling.

Check that the silver part of the engine cover isnt loose.

[Stompie]

serious? i know its loose, will remove it and check if it goes away

[ruler_70]

Its a long shot, but i really hope its sorts out your problem.

[Stompie]

mee too!!! its been going on since last year, took it to FRC, they put it on the lift and checked for leaks arround the turbo but couldnt find anything...i simply cant see wat is causing this....and car was dynoed with this and power was strong, i mean stock it was stronger that some other polo gti's. so im not loosing power....

[MeanTdi]

Have you fiddled with boost pipes or intake manifold to fit a boost gauge or something similar?

[Stompie]

nope, no boost gauge...sound started after i fited a cone filter last year, tried putting back the airbox and sound is still there...

[MeanTdi]

nope, no boost gauge...sound started after i fited a cone filter last year, tried putting back the airbox and sound is still there...

Try and look at what you have changed when you fitted the filter.

NB - did you reconnect that tiny tube that goes to the top of the airbox somewhere? Not sure if the GTI has it but there is one on the TDI airbox. I will try to find a pic...

[BatteryWorldPtaEast]

Does the GTI also have the vacuum hose on the airbox ?

Check where it is ,it needs to be connected to the intake.

Hope it helps.

[MeanTdi]

Does the GTI also have the vacuum hose on the airbox ?

Check where it is ,it needs to be connected to the intake.

Hope it helps.

That is what I was trying to describe above.

[Stompie]

@meantdi - no there isnt any blue tube on my airbox, on the side there is a pipe that sucks in air to warm up the catalytic converter...but that only sucks air when you start the car.

at first i had only the 90deg bend with cone, without any software or dv. this is how i started modding the car...lol, replaced DV with forge one, sound was still there, replaced the pancake tip with a brand new Forge TIP, sound is still there, checked exhause and decatted and sound still there, replaced the whole DP with wildcat one and new gasket, sound still there. now all i can think is that the manifold is cracked or the caskets between turbo and block is leaking...but if they were leaking, the sound would have become louder...

this is why i think its a crack??

[MeanTdi]

@meantdi - no there isnt any blue tube on my airbox, on the side there is a pipe that sucks in air to warm up the catalytic converter...but that only sucks air when you start the car.

Tube is not blue but black on the TDI. Most probably the GTI does not have one...

[Stompie]

how thick is this pipe?

because the one ive got on the side is about 40mm in diameter.

but that isnt a vacuum im sure.

[MeanTdi]

how thick is this pipe?

because the one ive got on the side is about 40mm in diameter.

but that isnt a vacuum im sure.

Tiny, 5mm max in diameter.

[Stompie]

no defnitley havent seen anything like that...? will have a look to make sure.

will a small pipe like that be able to make such a noise ?

[MeanTdi]

no defnitley havent seen anything like that...? will have a look to make sure.

will a small pipe like that be able to make such a noise ?

Not sure how load the noise is.

[Stompie]

the noise is coming from the driver side, if i open the passenger window and close the driver side i cant hear the noise.....if that maybe helps. also not loud! but you can hear it...

[MeanTdi]

I have uploaded a pic from a Seat Ibiza TDI. Like I said, the GTI may not have that tiny pipe going to the airbox...

[Stompie]

sup guys,

ok some good news, i took my car in for its 75k oil service yesterday at Bryanston VW and booked the car with frans.

went to fetch the car and frans asked me if i knew why my exhaust is so loud...i said no? but have a suspicion that the manifold is maybe cracked....

while doing the service he had a look and says its between the turbo and manifold. says it could either be the gasket or the manifold that wobbled where it connects to the turbo...

now, where can i get a new manifold and gasket and what would it cost? think i will first try a new gasket (cheaper option) and if the sound still stays then look at either repairing the manifold or replacing it (mabe with a bigger mani)

he also says that i will be loosing alot of power as the air is escaping before it hits the turbo so not spinning the turbo as strong as it should...

[Sinbad]

WHEN MY CAR IS FIXED just book it in for Frans to put a new gasket in for you.

[Sparkz0629]

WHEN MY CAR IS FIXED just book it in for Frans to put a new gasket in for you.

lol sinbad, you still waiting for your car????