The Ultimate 2.0T PCV Fix

We have seen it all. There are some good fixes out there for the car, one that is famous is the Digital Hippie PCV Fix. We took the time to explore the system a little further, and finally came up with this fix as the most reliable and cost effective PCV Fix for most 2.0T FSI engines out there.

The stock PCV system is prone to failure on the pressure side. The check valve can not block boost coming from the intake, so it will allow pressure to leak in to the crankcase (valve cover area). Ultimately this leads to a reduction in boost pressure in the manifold, and decreased performance is experienced by the driver.

The theory here is that you have two parts to the pcv system

1. A normal straight pipe to pre turbo (the "back" hard pipe).
2. The new pressure side.

If you block the pressure side, you eliminate boost leaks. But at what expense? Will there be pressure in the crankcase?

We set this system up to test:

Back side has a fitting that we ran to our boost gauge. Yay, needle moves ever so slightly into vacuum, but never, ever deviates into pressure.

So how can we make this easy? The hose is 7/8" ID hose with standard hose clamps. In the PCV section, these are labeled as 3/4" caps, the fit perfectly into 7/8" ID hose for some reason, and work great for the non pressure side.

Pressure side had a concern, would it hold? Probably not. Let's explore a 3/4" - 7/8" EXPAND A PLUG that we found at Advanced Auto.

Insert the plug, and use an extension and a 13mm to press it in. Make sure the nut is loose before starting.

Then only hand tighten using the socket and extension, do not use a ratchet or excessive force, as you'll probably crack your intake.

So our car felt sluggish before doing the testing. We hit only about 16-17psi. After the fix 22-23 all day!

We would like to hear your thoughts and concerns with this mod.

That's why we did the boost gauge fitting/hookup, because if there was any sort of positive pressure, this project would have been immediately aborted. And you could use two expand a plugs, one as pictured, and the other on the crankcase side.

A vent to atmosphere setup was tested, too. Using a filter off the crank side allowed unmetered air into the intake through the rear pcv pipe.

With two, you have the $4.00 Deviant:Speed PCV fix that has no reliability issues, yay!

Posted in | Submitted by deviantspeed on Tue, 2008-01-22 14:56.
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If you put a breather on the front side PCV, then the rear side will leak air pre-turbo, and after the maf.

The unmetered air will cause rough idling and improper/dangerous running. Please understand the different types of PCV setups on this car and how it works before considering this mod.

deviantspeed | Wed, 2008-07-09 13:32

Do you recommend placing a little breather filter on the PCV side instead of plugging it?

dk99 | Fri, 2008-06-06 13:33

Keep trying! We have received countless thanks since this modification was published, so the expanding plugs might have sold out! Have you tried Autozone if you have them up there? They have 'em down here, but maybe they need to order them?

deviantspeed | Wed, 2008-03-26 22:17

hey i live in washington state and cant find the expand a plug for the mkv pcv correction any suggestions?

Derekb21 | Mon, 2008-03-03 01:43

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