Help to locate boost hissing noise

[Willbo]

Sounds like a pipe or the intercooler is leaking to me

[5potnoodle]

Had this problem on my 200 once... the intercooler to intake rubber flexi bellows (michelin-man) pipe thingy had split but it wasn't noticable. I got the hissing and sounded like a dump valve when changing gear. I think somebody mentioned fingers in dykes... Get your fingers around the pipe on the bottom side and feel for the split. Mine had split underneath one of the metal rings on the underside of the pipe, couldn't see it but finger went in. Took it off and temporary repaired with a rubber o ring and some bycycle tube glue which worked for a while. Audi quoted me some ridiculous price but sourced an OEM replacement from the US, brand new for about £30.

[20vcqdriver]

Originally Posted by kerker21

oh come on guys its only a boost leak you havent got your finger in a dyke "cairfull johnson dyke as in sea defence" it will end up the simplest fix you have ever done its something come loose on the inlet tract not something worth slitting your wrists over

Thanks John, always rely on you to say it as it is .

The story in detail is this: Once upon a time...
Most know of the refurbed turbo fiasco and I have lived with this one smoking slightly and whining and moaning for a few months, Well last week all of a suddn the thing started hissing like a snake was behind the dash and thought the turbo had finally thrown its hand in, so changed it for the known working spare I have obtained, at the same time I thoroughly checked all the hoses from the turbo through chargecooler to metal pipe going to throttle, no signs of damage which is what I expected as I used new uprated Nomex Silicon hoses (take more hammer than normal silicon) when I fitted the chargecooler at Christmas, so this has been ruled out. So I now have no smoke, no whining or moaning, just a snake to find..
Having checked the non return valves to the servo and found them ok and tested all the vac hose connections from the inlet, I am of the opinion it is either the short pipe that joins to the throttle body, gasket between throttle body and manifold or gasket from manifold to head. All of which will cost me money to fix, so cycled into work this morning to save fuel (dodging the rain) and will cycle all next week to save enough for at least some gaskets (£5 day). Am sure I will get it running right eventually but theres a good chance I'll be retired by the time that happens... am I just unlucky or are these engines always this unreliable?

[BW2309]

Don't lose hope, these engines are bomb proof and very reliable! My mate's running his 350+bhp S2 coupe I built the engine for 4years ago and it's never put a foot wrong. Done loads of 'em with very little trouble.

There's little point me adding to possible leak points as just about every joint on the car's already been mentioned. A good, methodical hour or two max on the car should highlight any issue and then once it's rectified you'll love it again!

Best way to tackle it is to start with fresh sheet of paper - ignore what you've already found and just go through the engine bay. Check all boost points, ISV for leak by, throttle valve, condition and correct choice of injectors, fuel pressure, boost feed to ECU (with it's dampening tank) etc etc. I am sure you'd find there's just a few minor things that are all adding up to mess you about and lead you astray in terms of diagnosis!


Good luck - don't give up!

[20vcqdriver]

Originally Posted by BW2309

Don't lose hope, these engines are bomb proof and very reliable! My mate's running his 350+bhp S2 coupe I built the engine for 4years ago and it's never put a foot wrong. Done loads of 'em with very little trouble.


Good luck - don't give up!

Are you volunteering to rebuild/ upgrade the bottom end of mine late next year then (funds permitting) and assuming its running properly by then.

[20vcqdriver]

Well after a quick beg, steal and borrow with the engineering company I use at work, they came up with this 2 hours later (see pics)...
Fits K24 outlet hose. Let you know how I get on...
If anyone needs to borrow it afterwards, let me know..

[BW2309]

Originally Posted by 20vcqdriver

Are you volunteering to rebuild/ upgrade the bottom end of mine late next year then (funds permitting) and assuming its running properly by then.

Absolutely!!!
I love these engines. Very intrested in the newer FSi/TDi stuff and the technilogy is simply brilliant but the old 20vT 5pot will always be my favouraite of all Audi's engines. So much character and such a strong engine, both in terms of life span and it's power delievery. A good one is simply brilliant!

Well worth persevereing!

[20vcqdriver]

Right, Used the adapter and found a small leak on the throttle housing to manifold so sorted this out with a replacement gasket and put it all back together as i stupidly thought that was it. Re-tested and still a lot of air escaping and took a lot of locating but eventually found a hairline crack in about the only part not changed during the conversion...the short hose from throttle body to metal intake pipe over the cam cover. So off it all came again and Superglued for now but need a replacement 034133649C hose. Not sure how much it is but cost will dictate how much cycling I need to do.. Unless Amanda has one in her loft....Er Hmm

[kerker21]

dave keep away shes got swine flu at the mo either that or its another case of the wirrel sniffels again , post a pic as iv a few lengths of differant sized samco hose in the garage i can cut you a piece of to what you need

[20vcqdriver]

Originally Posted by kerker21

dave keep away shes got swine flu at the mo either that or its another case of the wirrel sniffels again , post a pic as iv a few lengths of differant sized samco hose in the garage i can cut you a piece of to what you need

Thanks for the warning and thanks for offer of hose, but unfortunately it is the part with a take off for the ISV and reduces accross its length, just to make things awkward...