MK7 and MK8 PCV Info
If you’ve been following from the beginning, then you know that this entire PCV research thing has gotten a little out of hand. If you want to get a pretty solid understanding of how an OE valve works, this video from 2023 is a great place to start. This goes in-depth on the internal workings of the valves, and was where the MK8 retrofit experiment started. There might be a few items in this video which are now better understood, but all in all it is a good foundation. There are MANY videos at the bottom of this page if you’d like to nerd out even further.
Smoking problems
Regardless of which PCV solution(s) you are considering, this video is essentially a 12 minute breakdown of all the factors at play you need to be aware of when trying to solve smoking problems. Some bonus info on the video is located HERE. Also see the diagnostic flow chart below.
PCV Diagnostic Flow Chart
I created the following flow chart which essentially encompasses my personal thought process when considering a specific car, turbo, use-case, etc. There is a LOT of information spread out over several hours of video from learning over the past two years. Based on everything learned, this would be my diagnostic process in pursuit of eliminating smoking with the goal of minimal compromise for daily use.
On mobile: Zoom in or long-press and open in a new tab (or save) for easier viewing.
MK8 Retrofit Parts List
(Note: Prices updated July 2025 to reflect recent changes)
Basic Retrofit Parts List:
06K-103-210-D (PCV hose) - 2021+ Tiguan, approximately $136 $170
06Q-103-495-B or 06Q-103-495-G (PCV valve) - 2022+ GTI/Golf R, approximately $64 $24
The original 495-B valve has been superseded by the 495-G valve. Both are fine, though it appears there was a very minor revision to the diaphragm. I see no reason to specifically seek out or avoid one version or the other.
06M-906-094 (bung) - Unknown application, approximately $14
Dorman 47395 (3/8 Vacuum cap) - not required if doing Full Retrofit, recommend sourcing something similar locally, should be < $5
Additional Parts needed for Full Retrofit with OEM style turbo outlet/OEM size charge pipes:
034 Turbo muffler delete - approximately $113 $135
90 degree fitting - only ONE of the following two are needed, see notes
1/8npt to 3/8 barb fitting: approximately $8 - this is what I originally used though it is a pretty tight fit and works
1/8npt to 5/16 barb fitting: approximately $8 - this or similar is more ideal
1/8npt extensions - approximately $7 - may need one or both included to clear the turbo muffler. See video on Full Retrofit Specifics below for details.
If you have non-standard turbo charge pipes/cannot use the 034 TMD for Full Retrofit:
If you have a turbo that does NOT use a turbo muffler adapter or you have non-standard size charge pipes, you will need to tap for pressure somewhere between the turbo OUTLET and the THROTTLE BODY. Some charge pipes may have a 1/8npt fitting intended for water/meth injection, or you can possibly use:
- Mishimoto 1/8" hose/coupler tap
- Have a bung welded to your charge pipe if it is aluminum
- If your charge pipe is thick enough, just plain tapping for a 1/8npt fitting (and using some sealant) should work as well. Verify it's not leaking!
See the “Confirmed: Turbo Inlet Pipes can Break our PCV Systems” video below.
Videos
These are some of the more information-specific videos, all placed here for quick reference. The FULL PCV Playlist has a LOT more that you may like if you really want to geek out. Alternatively, you can go through the Improving the Car > Drivetrain/Cooling section of the website where these videos will be linked, along with some supplemental info to go with them in most cases (data from the videos, etc.).