Big Boost leak

**Militant-Grunt** · 09-24-2008 10:34 PM

Alright, I'm just about fed up.

Ive been trying to hunt this leak down for the longest times now. It is a massive leak, when I get on the power it is an audible loud hiss coming from the left side of the engine.

I have a pressure tester that I made and found every single leak the motor had. Today I completed this mod: http://www.audizine.com/forum/showthread.php?t=235106 I did 90% of it, just waiting on my Integrated Engineering plate to take out the EGR. I capped all the unused ports and clamped down the caps. Even without the EGR taken out know there's no way the leak could be coming from there. When I pressure test the motor through the throttle body, I no longer have hiss, in fact the motor holds pressure so well when I pull off the tester excess pressure is released. My pressure tester is type shitty and I can't mount it on the turbo or on the tip hence I got to go from the tb. Now that I eliminated the hoses on the engine the leak has to lie somewhere between tip and throttle body hose.

I checked the TB hose: No rips
Checked the IC hose: No rips
I put in an APR silicone inlet hose and made sure everything attached to it is tight.
I replaced the turbo outlet hose to the one off my old 98.5, had to retrofit to the old style removing the two piece dv hose. Checked for rips

What remains is the intercooler and the actual piping in the bumper support.
How often to oem intercoolers develop leaks?

I wanted to try a S4 intercooler that our shop has lying around but the 2001 1.8t has a map sensor built into the housing. I visually inspected the intercooler and could not see any problems with it.

This is a month long pain in the ass id like to finish already, any ideas/ help would be nice.

**Devious27t** · 09-24-2008 10:35 PM

have you pressure tested your intercooler?

**Militant-Grunt** · 09-25-2008 10:00 AM

Not as of yet, thats on my todo list for today.

**B5A4Kevin** · 09-25-2008 06:53 PM

i know you say it sounds like drivers side but have you checked your DV? a bad diaphragm can cause a fairly large internal and audible leak. low boost is a symptom though.

**Militant-Grunt** · 09-26-2008 09:47 PM

I found the whore of the leak, a 1 inch long tear on the turbo outlet hose, the one I replaced, must've cracked shortly after I replaced it, out of all things. I ended up pressure testing the entire system bit by bit, while under the car I noticed the rip.

For the first time after a month of ownership I know what the car is supposed to pull like.

I'm set at 19psi and the car pulls stronger than a customers 2000 1.8t A4 k04 w/ j-31 (injectors fmic full exhaust) While I have the k03s a custom tune (SSP base revision 1) and a full 3" turbo back and silicone inlet pipe.