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Old 10-04-2006, 03:01 AM   #1
Scooby Specialist
Member#: 85227
Join Date: Apr 2005
Chapter/Region: VIC
Location: Vancouver, BC, Canada
2005 STI

Default 05 STI - COBB uppipe install - I can't stop the leaking

I bought new gaskets for the uppipe to turbo and uppipe to manifold.

I reused the manifold to block gasket, and the manifold to crosspipe gasket. Before somebody flames me on that, my theory is that if the parts on both sides of the gasket are not being replaced, reusing the gasket should be fine since each part on either side has taken a "set" into the gasket. I've also read of numerous uppipe installs that went fine with replacing only the 2 uppipe gaskets and reusing the other 2. I'm also pretty certain it is not leaking in the 2 manifold gaskets. The "smell" test indicated the leaks are from the uppipe.

This is what I did:

1. Finger tightened everything (and I mean really loosely... I could still shake everything around a few mm).
1. Torqued manifold to crosspipe 15, 20, 25, then 30 ftlbs in steps.
2. Torqued manifold to uppipe 15, 20, 25, then 30 ftlbs.
3. Torqued manifold to block 15, 20, 25, then 30 ftlbs.
4. Torqued uppipe to turbo (3 bolts only) 15, 20, 25, then 30 ftlbs.
5. Torqued uppipe to support brackets (2 bolts) 20, then 30 ftlbs.

Reason I did the 3 bolts separately is because those are the ones where the gasket are. Once those make the seal, then the 2 support bracket bolts were tightened. If I had tightened the 2 support bracket bolts, it might have affected the seal on the gasket.

I am still getting the hissing sound... it is not nearly as bad as before, but it is still there. This is the most frustrating thing ever. Any suggestions?
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Old 10-04-2006, 06:09 AM   #2
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Join Date: Jan 2006
Chapter/Region: SCIC
Location: Orange
05 GarageTuningSTI
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are you sure you are still leaking ??? or probably drive it a bit and let the new gaskets burn. If still leaking after that, you just have to tighten it more or replace gaskets..
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Old 10-04-2006, 08:50 AM   #3
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Member#: 59692
Join Date: Apr 2004
Location: Cincinnati
2005 Impreza WRX STi


Put the stock uppipe back on or use an aftermarket pipe with a flex joint. Uppipes without a flex joint tend to leak. The stock pipe has a flex joint...that should be your first clue.
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Old 10-04-2006, 11:14 AM   #4
Turn in Concepts
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Join Date: Aug 2005
Chapter/Region: MWSOC
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You first have to figure out where it is leaking. Look for black marks around the joints, or get under the car when it is running to listen. From there I would get some high temp copper rtv and go to town on the leaking joint. That should seal it up rather well.

FWIW, I have pulled my UP out of my wrx 2 or 3 times, pulled my manifold at least 5 times and had my turbo(s) off a few times and have yet to replace any gaskets. I am not saying this is ideal and for some would cause problems, but I think in this case you are ok. The last time I had a leak, it was from the driver's side manifold to crosspipe joint. I had the two bolts torqued down to 35lbft, but it was still leaking form there. One of the bolts was somewhat crossthreaded somehow and was not tightening down enough to seal. I cranked it down temprarily until I got a new bolt and it sealed fine.
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