MK7 PCV Analysis - How it works, and why I've adapted the MK8 PCV (Pt 5)

[@mrwest77]

It's the third time I see this video and every time I understand something more (also because of my english listening skills). Really usefull, even for Mk6 owners (I guess)

[@SeanJuan_]

Very informative video, thanks for taking the time to put it together. I’ve been looking into ways to improve upon the mk7 system recently. The PCV replacement plates have always made me skeptical, as have catch cans. The vacuum analysis on the catch cans has made up my mind about avoiding them. The system I am considering is adapting an air oil separator from AIG/Cobb designed for WRX/STI applications. The return line that would attach to the turbo inlet has a one way valve in it and by utilizing two of them, one on the side feeding the AOS and the other going to the turbo inlet, seems capable of fixing the vacuum problem created by the catch can. The oil return line I think would have to be directed to the oil pan. I think between this system and retrofitting the mk8 PCV system could virtually eliminate oil making it into the intake system.

[@datadrivenmqb]

That won't solve anything because the bottom end is constantly depleting the vacuum. Either way it still does nothing to solve any oil going through the blue path. Check out the other videos in the PCV playlist, been doing a lot of work with the Tiguan Venturi. Once I have the suspension stuff back on my car, I have a bunch of PCV and TIP testing to do. The turbo inlet greatly influences the entire system.

[@eppyz]

This was a very informative video, and was presented very well. A couple of things. 1. What was not mentioned about an aftermarket "catch can" is use in the winter months in cold climates. Catch cans fill 90% or more with basically water. When you live somewhere cold the catch can freezes and causes havoc. 2. This testing is from the perspective of "track use" for the OEM MK7 PCV vs the MK8. I would like to see that data just from what 95% of people that drive GTI's do and just have daily street use logs. I am sure the difference between these two PCV systems may not be as noticeable. 3. Keep in mind ANY modification of the PCV system is a smog violation in many states. Will an inspector actually notice this? Probably not, but still. 4. Lastly, I would love to see a video of an actual install of the MK8 PCV on a MK7/7.5 GTI. Appreciate the part numbers and all the info here.

[@datadrivenmqb]

Thanks! Pretty much all of that has been covered since. Links to most relevant videos here: www.datadrivenmqb.com/mk8pcv

[@eppyz]

@@datadrivenmqb Thank You did find them after watching this video. So the MK8 PCV and Tiguan PCV hose and capped is the better system to use for a stock DD MK7.5? Or just keep using the MK7 OEM unit? I will never track my GTI got that all out of my system with my past Lancer Evo's. I have been told to replace the PCV every 30k miles in these cars for preventive maintenance is this true?

[@datadrivenmqb]

@@eppyz the MK8 system (w/ Venturi) is very good. IMO if you have no issues then I wouldn’t worry about changing anything. Don’t go fixing problems you don’t have. As far as maintenance items go… A friend has 120k on his OEM PCV with tons of track use (and OEM TIP). I’d consider it a 60-80k item if you wanted to do it preventatively, def not a 30k type frequency.

[@eppyz]

Ok that is great news. I just live in an EXTREMELY Hot & Dusty climate and try to replace things before they need replacing. What is your feeling about DSG fluid with the 7spd in the MK7.5 GTI? VW states 80k but doesn't give a time frame. I am retired and don't drive much anymore, my car has 27k on it and is 4 1/2 yrs old. I was going to have the Coolant and DSG fluid changed due to age. Am I being to cautious? @@datadrivenmqb

[@lameio]

Very informative video, I'm here because I want to understand how the PCV system works, and how it may be causing my car to burn oil. I've got a 2015 golf with the gen 3 ea888 1.8, and recently replaced the PCV unit. Currently monitoring my oil levels to see if it's still burning.

[@r3spect21]

Is it still burning?

[@lameio]

@@r3spect21 not 100% sure yet, I'm still monitoring thr oil levels for a bit but I do think they went down slightly

[@lameio]

@@r3spect21update: shes still burning. :(

[@r3spect21]

@@lameiodamn sorry to hear that im about to change my pvc just was hoping that would fix the burning but i guess not :/

[@lameio]

@@r3spect21 there's a chance it could fix it. There's a way to test: while the car is running at idle, unscrew the oil cap and try to take it off (the car will run like crap for a sec that's fine) if the cap is relatively easy to take off, the pcv is fine, if it's stuck down, the pcv is broken. There's also a chance it could be turbo seals or piston rings. I'm doing a compression test tomorrow so I can let you know how that goes

[@JimMcBob42069]

Im so happy you are here

[@n8marsh]

Great video! Thank for taking the time to explain how it works.

[@xXxXFALL3NXxXx]

This is a good video with a lot of info about this system and problem, but I feel like the reason for a catch is more about preventing that oil cloud that occurs in certain turns on track. There have been mixed results on the forums with many users experience an inline can and replacement PCV system solving this issue while some users still experiencing that clouding effect regardless of a catch can. From what I can take from it is the revision of PCV valve that is is installed has an effect as some revisions were better than others.

[@datadrivenmqb]

Correct. In case it wasn't clear in the video - I think that how well a given PCV (any of the MK7 revisions, or the MK8 part) works on track is entirely from how much oil makes it through the bypass valve. I think that adding catch cans makes the issue worse by pulling more oil due to the delay of vacuum depleting on lift-off, plus delay of generating vacuum on tip-in. I think people install inline cans, which "breaks" the stock PCV system and makes them fill up excessively fast and people point to the oil in the can as "proof"... when in reality if you dump the can 1.5qts worth over the course of a weekend on track... the truth is that if NO can were present, you'd not be seeing that same 1.5 quarts in the intercooler piping. Catch cans with the stock system I think screw with the "timing" (for lack of better words) of the opening and closing of valves... and perhaps "tuning" the size of catch can may help draw JUST ENOUGH air towards the catch can/TIP to keep from entering the blue intake path, but not so large that they're sucking all the oil right out of the bypass valve. From what I've seen on MK7 valves, the BMS catch can seems to have the best (anecdotal) success rate since it's a very small can, with short hose runs. It does not fill up quickly according to anyone I've spoken with running it. For SCCA STH autocross classing purposes... if the "BL" revision PCV doesn't fix smoking issues on course, I'd probably be inclined to try the BMC CC personally (since retrofitting a MK8 valve is technically not allowed).

[@xXxXFALL3NXxXx]

@@datadrivenmqb Well that would work for your point, but there have been many people who have installed either an inline can or a full system replacement who haven't caught anything after months of use. This could be do to the climate that they live in if I remember correctly, but there have been people who haven't seen a single drop in their can. Also, some if not most of the gunk doesnt appear to be oil. There can be some oil in there, but its mostly more of a liquid substance; I can't remember what it was off the top of my head.

[@datadrivenmqb]

@@xXxXFALL3NXxXx this is talking strictly for track or autocross use. The high RPM on-off-on throttle is what causes issues. We have 5-8 MQB cars that regularly show up at TSCC autocrosses and track events. One guy in particular has zero problems with his catch can on the street, but fills the entire thing up in 4 or 5 autocross runs. How quickly they fill up is 100% dependent on how they're driven (and in normal driving - climate as you mentioned, particularly in winter time they'll catch condensation as you said).

[@xXxXFALL3NXxXx]

@@datadrivenmqb I see your point and agree with you that it is dependent on those driving conditions. Taking away from the video and this that the better solution is to run the MK8 revision PCV valve over a replacement and inline can? I know why some people would probably stick with aftermarket solutions as they have solved that smoke plume on certain track condition driving that is a common problem on this platform. It's the reason why I am looking into a catch can.

[@datadrivenmqb]

⁠@@xXxXFALL3NXxXx Yes if oil does not make it into the blue path to begin with, you won't have a smoke plume. This is solving exactly that problem. Every knock event happened with hard RH turns which always followed braking events. While I never noticed smoke while driving, it did occur to some small degree (and caught it in one video if you poke around my channel videos). Catch cans (with stock PCV) only help with oil in the TIP connection - which is NOT where any oil plume smoke is coming from. PCV plate replacements will fix smoking, but they pressurize the crankcase under low load and potentially braking as well - which is less than ideal. I have a friend sending me an APR CC/PCV plate kit to test out. I'll be documenting it here to see if the crankcase pressure is acceptable or could be a problem for long term seal life, etc.

[@_BestViralClips_]

Thank you so much for the informative video! This might be a stretch here but I’m hoping maybe you can provide some advice. I have a 2019 GTI with an aftermarket turbo/downpipe. Car has had 0 issues the entire time I’ve owned it. For the last year or so now on warm start and occasionally on a cold start I get a puff of blue smoke coming from the exhaust. I hear two things from people, bad PCV and valve steam seals or valve guides being worn. What would you bet your money on it being? I know I won’t know until the car is at a shop but if it’s a bad PCV I can probably replace it myself and wouldn’t be that expensive, but I’ve heard valve stem seals is a costly job. I don’t think it’s my turbo as I’ve never had a problem with it but I could be wrong. Any help is much appreciated! Thanks!

[@datadrivenmqb]

Honestly it could be either one, though I'd be more inclined to bet on valve seals given the symptoms... BUT I've had several people reach out and tell me that either new PCV valves or MK8 retrofit sorted out the same symptoms which I would normally not expect personally. A brand new BK PCV valve is actually only ~$50 from the dealer: vw.oempartsonline.com/oem-parts/volkswagen-engine-crankcase-vent-valve-6k103495bk That price is cheaper than shop labor for diagnosis... so realistically I'd put the valve on and if it stops the smoking, great... if not, at least you got a new valve to rule out as the issue, and you have a pretty good idea of what it really needs at that point. I'm not generally a fan of using the parts cannon to diagnose, but sometimes it makes financial sense when the cost to replace something is so low and relatively easy that it comes in below what an hour of shop diagnostic time would be.

[@_BestViralClips_]

@@datadrivenmqb Thank you so much for responding! I will go ahead and purchase that PCV valve and give it a go. If it is my valve seals what would be a fair price to get it fixed and is it something I should fix quickly? Your help is much appreciated!

[@JustinPike]

Thank you for the insight into the system. Also thanks for the explanation of the PCV plate replacements specifically. I now understand much better why my motor is blowing out oil seals. 😂 Pretty sure my rear main has been blown out, guess it’s time for an upgrade on that seal and perhaps revert to MK8 PCV system. ❤

[@datadrivenmqb]

No problem! Yeah I think there's a LOT of variation motor to motor, and the ill effects of plates vary greatly, with higher mileage or cars pushed for the ragged edge being worse off. The MK8 valve hasn't been 100% successful for all cars, but those that it hasn't have also had issues with near every stock PCV also. I'll be doing a follow up soon as I gather data from people that have retrofitted. I do think adding the venturi is key to best rate of success if you watch the other videos in the PCV playlist. An 034 TMD is the easy button for adding the boost hose as outlined in another video on the playlist.

[@catinthehat5140]

@@datadrivenmqb If you use a plate doesn't that cause a slight increase in crankcase pressure, especially if you drive aggressively? Meaning that even if it's a slight increase over time it will slowly push out your rear main seal?

[@SRalgarve1965]

Does the oil separator fails were boost gets in to the crankcase??

[@datadrivenmqb]

Most people don't understand anything about this system. If the one way check valve fails (just inside the blue passage) then it'll push boost pressure into the outer area of the valve, but much will just be vented into the TIP with some on the crankcase. But it won't be like putting 25psi or whatever straight to the crankcase. Most common failure (of MK7 valves) seems to be the diaphragm ripping, which means it's loses the atmosheric pressure reference and it because an intake air leak at idle while also not closing the diaphragm.

[@SRalgarve1965]

@ Yes I’m familiar with the diaphragm failure but was wondering if there was a possibility of getting boost in the crankcase thru one of those check valves, thanks for the response

[@datadrivenmqb]

@ no problem. In a nut shell it moreso interferes with blowby escaping than directly pressurizing the crankcase significantly.

[@lamazver]

Nice. I'm gone to order parts needed. Thanks a bunch💪🏻🍻

[@jeremymitchell8470]

Did you choose the Tiguan hose for length/shape, or was it due to the fact that it happened to have the correct connections for your application? I'm searching for info on how to get a little more length on my Mk8 PCV hose since I have a Pmax going in next month. Everyone that has done that install on the Mk8 said that the worst part was the PCV hose and that there is quite a bit of stress put on it. I'm trying to prevent any issues during install so I was hoping to find an OEM solution (slightly longer PCV hose or fitting) like you found for your application.

[@datadrivenmqb]

The hose is from a Gen 3B Tiguan (EA888.3B), which happens to use a turbo inlet pipe (and TIP PCV connection) identical to the EA888.3. The EA888.4 PCV in the MK8 is considerably different as there is no TIP connection, the hose goes straight to a fitting on the turbo which connects the turbo inlet housing to the turbo outlet housing. It can be seen here: kzbin.info/www/bejne/oIrHd2CphLGYaassi=LQ4oykVl-YiHtYk-&t=1404

[@anthonyjose5644]

Dude I really appreciate this video thank you so much

[@HankeB]

I think I'll be ordering some parts soon for my mk7 GTI. I have a different intake and turbo inlet pipe, so I'll have some info on it once i can make an autocross event and a track day.

[@datadrivenmqb]

Do you happen to have problems already? Just to be clear if your PCV system is working just fine, I'd be sure to leave well enough alone. Otherwise if you do go through with retrofitting the MK8, definitely report back!

[@Denydee-uw8ki]

Im not a mechanic, but like all mens ... logic of thing is very important to us. Thank you for sharing this much infos, but i wanna ask you a question if its possible. My golf mk7 2015 1.6tdi bluemotion makes smoke from oil cap, even on a cold start ??? Any idea, because im new with Golf tdi and im thinking is any serious issue with engine ???

[@datadrivenmqb]

@@Denydee-uw8ki diesels function very differently - there is no vacuum in the intake manifold available to potentially act like the EA888.3 at idle. Would need to find someone more knowledgeable on VW TDI stuff specifically.

[@SoldSane]

What a great video. Thank you! 🙏

[@adriansandoval5505]

😍💯 like the way you explained it keep the videos coming

[@W0LV1E45]

have ypu figured out what that sensor does? It's a map sensor but why would VW decide to put a map sensor? If you unplug it you'll get P0453 and P0452 (i'm havi g P0452 problem on my MK8 GTI and still has it after replacing gas cap and evap leak detection pump). I didn"t know until I saw a thread titled "P0453 code on MK8 golf r" on vwforum and when I unplug the connector to the sensor I get P0453 (I assume my Pressure sensor has failed (I could get it fixed under warranty if I didn't get a tune) while diagnosing it.

[@datadrivenmqb]

@@W0LV1E45 it measures the PCV vacuum source. Can also capture positive pressure crankcase events. Sounds like you might have a failed valve. Pressure sensor failure is relatively uncommon.

[@W0LV1E45]

@@datadrivenmqb I replaced it and the code P0452 disappears. I'm so pissed since I bought a new evap leak detection pump for it twice but both didn't work. Turns out it is that map sensor on top of that pcv valve that is the culprit. I thought it was the wiring at first so I stripped the tape to check the condition.

[@datadrivenmqb]

@@W0LV1E45 yeah, if the EVAP system doesn't have a sufficient vacuum source OR if it ever sees pressure or a lack of vacuum when it's expecting to see vacuum, it'll set that EVAP DTC.

[@JordieG8]

I just did the valve retrofit on my S3 without the venturi with a P-Max 2260S and an IE intake. I would be interesting to compare the effects of aftermarket intakes on the PCV system under boost. Thanks for your work on this.

[@patrykkrol9433]

I also have a Pmax and I was thinking about making a hole in the bottom pipe and connecting this cable. as it is for the venturi. and you plugged this cable and everything is fine. ?

[@JordieG8]

@@patrykkrol9433 yes, the boost control system was able to compensate for the increased airflow of the Venturi. I drilled a hole in the reinforced section of the factory boost pipe and installed an NPT fitting. It worked well.

[@patrykkrol9433]

​@@JordieG8 good to be able to do that. and there are no EPC errors etc? Can you share any photos of how to do it on WhatsApp?

[@JordieG8]

@@patrykkrol9433 sure.

[@NDPhotonl]

What happens if you open op the AOS hole on the MK7 PCV valve, thats one of the differences right?

[@datadrivenmqb]

@@NDPhotonl haven't done it. No way to clean inside the valve if any shavings break free which would either clog the valve or go into the engine.

[@matosaric6811]

Wish I’ve seen this video some months ago, excellent! One question - I’ve had problems with blue smoke when leaving from redlights, or going on throttle after longer coasting or idle. It was exactly same symptoms as bad valve stems. Then i removed the vwr racingline catch can with pcv (blocking) plate and put the stock pcv and the blue smoke stopped. The upper vwr pcv plate had a bolt missing and slight oil leakage. I can’t figure out if it was the leakage causing the smoke, or if it was overpressure in crankhouse that caused the leakage and smoke. Any thoughts?

[@datadrivenmqb]

@matosaric6811 It's hard to say for sure without seeing/assessing it myself... My guess is it's a combo of both (light pressure on crankcase at idle is pushing past the valve stem seals). Might not necessarily mean failed/torn seals, but possibly just very weak ones that don't hold pressure. I actually have a crankcase pressure sensor rigged up that I can log now... so if I can get my hands on some kind of PCV plate systems locally, I'll be trying to test one at some point. Check out the latest video plus some of the others in my PCV Playlist for info: kzbin.info/www/bejne/mGismZelp92AY9Usi=OabDydi2jCysN0ow

[@matosaric6811]

@@datadrivenmqb Thanks, I’ve watched all the videos, great work 👍 I find it hard to understand how leaking seals, and thus less vacuum, could make more oil take the route through the catch can line and intake pipe on initial throttle. Unless the leakage goes through the ”blue lines” to the intake manifold? It’s feels like oil is piled up somewhere and then immediately sucked up and burned on first blip on throttle. I have no issues with smoke on the track. Btw. I’m running vwr intake pipe, airbox and elbow.

[@datadrivenmqb]

​@@matosaric6811 basically if you have an additional pressure source in the crankcase (boost directly past the valve seals, in addition to the normal expected blow-by past the piston rings), then it is that much more that must be drawn on to maintain a constant vacuum. More airflow required to maintain a vacuum = more of a "straw" effect that the engine block passage turns into. For an analogy: think of filling a cup of water that has a tiny hole in the bottom. You can keep it "full" if the hole is small enough. But if you introduce another, maybe large hole.. it requires pouring water at a faster rate to keep it full. It is basically the same deal, except trying to draw vacuum on a "sealed" system. Thanks again, and hoping to have a lot more answers real soon.

[@eoghanhennessy443]

Has any body got an oil light on because of this . Having trouble with 2016 golf r . Engines geting low oil pressure engines been completely rebuilt. I replaced the faulty pcv but doesnt seem to have help . Any help be great . Its had new cam shafts as well ❤

[@datadrivenmqb]

Oil pressure is a mechanical problem. Either the engine wasn't built right, or you have one or multiple bad oil pressure sensors. There are something like 4 of them if I recall correctly. Two on the filter housing, one down near the crank pulley, and one on the front side of the car closer to the transmission if memory is correct.

[@eoghanhennessy443]

Iv seen a video replacing the pcv fixed the oil pressure a guy figured . It raised his oil pressure 6 psi . ..any way didnt fix mine . . There is an oil control valve on the bottom front of the timing cover . If u leave it connected or not connected it doesnt seem to effect the oil pressure in the engine . Iv ordered a new one but not sure if will fix it . There is also one on filter housing . We have replace that it didnt help the pressure when cold goes from 60 psi to nearly 5 psi when warm . We have the oil pressure testers in the filter housing . Theres seems to be a 5 psi difference between each gauge . Im not sure what pressure the engine should have we are struggling to get data on it . Abd even if we are ment to check the pressure there are there is a another pressure sensor on front of block

[@Renaldo181]

I have a 2016 Golf R and from 3k rpm upwards I see smoke from the exhaust and the oil consumption is also high. What do you suggest I do with my PCV?

[@datadrivenmqb]

@@Renaldo181 start with performing compression and leak-down tests. No sense in throwing parts at a car without verifying mechanical condition. If it’s all the time under those conditions, that sounds less like PCV and more like something else, but I’d at least rule out mechanical issues first. Also make sure the oil isn’t overfilled.

[@Renaldo181]

@@datadrivenmqb yeah thats what I was thinking too. I have it booked for tomorrow. It only gives puffs of smoke under boost and also soot on the back or my car so I think there is a series of problems.

[@Next-nb9pr]

Can i improve te older pcv by drilling bigger hole in drain ?

[@datadrivenmqb]

It hasn't been tested yet. If you check out some more videos in the PCV Playlist.. I'm not entirely sure that is the root problem or would have any effect now that I've done some more testing and gotten data from others: kzbin.info/aero/PLM3GfuZIZ1rYy7_ssLmeIEbzurgmb1GRH

[@webbyhawk_mk7]

I have a 2017 GSW 4motion and it smells like gas fumes aftwr drivng and pulling to a stop, could this be caused by the PCV system?

[@datadrivenmqb]

Probably not. Sounds more like something EVAP or fuel system related but it's hard to say not seeing it in front of me.

[@webbyhawk_mk7]

@datadrivenmqb okay I've replaced the fuel pump seal and kinda at a loss for what to try next, my issue doesn't seem to be common

[@miigotu]

Possible to remove the check valve at the TIP side of the PCV and add a check valve close to the TIP, so the volume of air between the check valve and low vacuum is smaller?

[@datadrivenmqb]

If the vacuum gets depleted (like it does when going from off to on throttle) it won’t make much of a difference either way. Doing the full retrofit w/ Venturi helps the most. More info has been learned since this original video. www.datadrivenmqb.com/mk8pcv

[@catinthehat5140]

I really respect this information and your testing. I'm always worried about products like catch cans because what if they know it doesn't help, will they stop making it? Will they actually say this? On a DI engine VW would want to avoid oil in the intake as much as possible so you'd assume their PCV design would be optimized for that.

[@datadrivenmqb]

Thanks! I joke that VW probably pays some dude to listen to door chimes more money than what the aftermarket has put into R&D on the PCV system. You just aren't going to get OEM levels of development and true testing in the aftermarket. This is something I learned over the course of many years as a tech.

[@catinthehat5140]

@datadrivenmqb you mentioned that if the crankcase pressure exceeds some value, a relief valve opens. Does this cause some of the oil in the pcv reservoir to enter the turbo intake?

[@datadrivenmqb]

@@catinthehat5140 at what timestamp are you referring to?

[@catinthehat5140]

@@datadrivenmqb 9:39. to about 11:30

[@jesusalejandroconsuegra8939]

Hello, I have a problem with my VW Golf 7.5 R stage 3, when I install the racinline, barteck or apr pcv the car smokes, at idle and in motion, however not with the original, is there a solution for this?

[@datadrivenmqb]

I’d start with compression and leakdown checks, and if those both are OK I’d consider checking the valve seals (won’t show up on either of those tests). Sounds like there’s something physically wrong with the engine so I’d rule all of that out before anything else.

[@S.Double.0h]

I wish I found this video earlier as I just installed a plate catch can on my Mk7.5 GTI.

[@catinthehat5140]

VW knows that with a DI engine oil through the intake is terrible, will cake up the valves (carbon deposits + oil). It looks like they improved the PCV to reduce the amount of oil except under high load. Which isn't as bad due to the pressure??

[@JoediyLab]

Great video, when autocrossing, what data logger are you using? Is the knock sensor data coming from VCDS? If so what settings are you logging? Thanks again.

[@datadrivenmqb]

@@JoediyLab it's using Simos Tools. www.datadrivenmqb.com/diy-data/st-getting-started If you're on FB, check out the Simos Tools Users group.

[@BoRnNiTrO]

If the pcv was failing or failed, could it cause any bungs/plugs on the timing chain covers to unseal and leak oil ?

[@datadrivenmqb]

Failed PCV can cause increased crankcase pressure, which could show up as cam cover or timing cover leaks, yes.

[@BoRnNiTrO]

@@datadrivenmqb cheers mate my inspection Bung popped twice, chnsged my pcv now

[@jimkamradt7243]

I have a 2021 Atlas with the 2l turbo. How can I tell which version I have, and does this issue apply to a street driven car vs. competition? How can I reach you?

[@datadrivenmqb]

That should have a regular MK7 style PCV system. I'm not sure of which valve revision specifically. These problems don't really show up unless you're doing autocross or road course stuff. If there aren't any "problems" with your PCV system, generally I recommend leaving well enough alone. One of the latest findings seems to suggest that aftermarket turbo inlet pipes might cause some issues with OEM PCVs. Check that video out here: kzbin.info/www/bejne/qomxhqmJd6ucjKcsi=1DmceZkEzShpCdRM Feel free to contact me through Facebook @datadrivenmqb. Or on www.golfmk7.com as user "Derhase".

[@jimkamradt7243]

Would it be okay to disassemble the pcv and clean it. My other concern is carbon build up on the valves. I'm contemplating cleaning with baking soda at 50k miles

[@datadrivenmqb]

@@jimkamradt7243 I suppose you could disassembly and clean the diaphragm assembly. All of the MK7 valves I've taken apart have had some indication of not sealing evenly in the center of the diaphragm. I suspect this is due to the way air flows through the valve (and will be immediately obvious if you remove the diaphragm cap). I'll also add that the MK7 valves are a much bigger pain to remove that cap due to lack of space around it near the back of the valve. I snapped one of the retaining clips on 2 of the 3 I disassembled. For peace of mind I'd probably err on the side of replacement. As for carbon buildup, I don't think it's significantly PCV related. These cars have no EGR valve so there is some sorcery involved with the intake vs exhaust cam timing to get an EGR effect which keeps NOx under control. Doing long term testing on multiple vehicles would be needed... but considering that catch cans make essentially zero measurable effect on carbon buildup (including those plates that block off the intake path) from all the "testing" *I* have personally seen, I think the intake valve deposits will just be a regular maintenance item to do every 60-100k depending on driving habits, etc.

[@baronbristow8764]

What happens if you just gut the whole plastic unit and put a one way valve between the pcv and intake (post turbo)

[@datadrivenmqb]

Will have a massive vacuum leak at idle due to the blue passage vacuum to the crankcase not being regulated by the diaphragm.

[@tomhunter91]

Wow that's a lot of knock. I've never seen that much and I drive my car like I stole it. HPA FR450, 29 PSIG, EQT pro tuned, 8.5" wheels 245 ps4s tires, Bilstein coilovers, 4 puck clutch, FBOs. Replaced my PCV with the newest revision last year which removed some rough idle issues I was seeing. Is this a problem with old revisions of the PCV or just any mk7 PCV?

[@datadrivenmqb]

Can happen from PCV failure, earlier revisions may be more prone to issues. This problem only really shows up in track/autocross situations until it’s REAL bad.

[@jakemasatti3292]

Could be a shot in the dark here but i've been having boost issues with my vortex xl mk7 R. Car makes 32-33psi just fine until i hit 7k rpms and then it spikes wgdc to 100% and sits around 31psi, we have gone over other possibilities such as pressure/smoke test and replacing the dv. So my question is do you think a failing mk7 pcv could cause an issue like this? Check valve potentially leaking a minor amount of boost only at high rpms?

[@datadrivenmqb]

Maybe... But I can't realistically see the PCV leaking so much to cause a notable hit in WGDC and not *also* do something wild like blow the rear main seal out, or smoke like crazy under boost. I'd venture to guess a failing turbo or maybe a restrictive exhaust not knowing anything else. I can't say I'd go straight to PCV based on your issue.

[@craiga9959]

ive ben having oil consumption issues on a mk 3 scirocco race car with e ea888 cawb engine. i was going to fit an aftermarket pcv with a catch can but im thinking id sooner give this a try

[@datadrivenmqb]

I'm not familiar with that engine - if it's an EA888.2 then I don't think any of this will really apply/be possible as far as the MK8 PCV retrofit goes.

[@Z.Z.V2]

What about the VTT Catch Can System? It's supposed to sufficiently pull a vacuum when it's not under vacuum from the turbo intake.. Haven't seen anyone test this.

[@datadrivenmqb]

I'm curious about it personally. But I've not seen a SINGLE person who actually has installed one. Seems odd to me, but likely since VTT has a poor reputation for customer service from a quick search maybe?

[@patrykkrol9433]

What engine (code/capacity) does this PVC cable come in in the Tiguan?

[@datadrivenmqb]

Whatever the Gen 3B motor is. All of the US spec 21+ Tiguans as far as I know. (2.0L)

[@patrykkrol9433]

@@datadrivenmqb ok, I've got it. I have a Pmax 1 and I want to drill a hole and put a connector in the lower factory rose. will this work? Have you done such a test, and what cut of the hole in the shortest length will be good?

[@datadrivenmqb]

@@patrykkrol9433 not sure exactly what you're describing. I have some info on www.datadrivenmqb.com/mk8pcv regarding fitting to non-standard turbos where the 034 TMD isn't an option.

[@patrykkrol9433]

​@@datadrivenmqbI want to connect this cable as in 034. only in pmax I have to make a hole and use an ntp connector

[@diydrivenGA]

Since you seem to have a much deeper understanding of this pcv system I was hoping for some info on the oil cap design on the MK7s. It seems they by design vent. Is this a sign of other issues and can it be resolved?

[@datadrivenmqb]

I think the cap venting is a "just in case" kind of deal. The spring is VERY strong. Small amount of wetness over a long period of time isn't a huge deal IMO. I think a lot of what is normally seen can be caused by people removing the oil cap and placing it upside down while doing an oil change. Oil on the bottom then runs all over to the outside of the oring that actually seals (the smaller diameter square cut o-ring, not the round one near the top). Time and heat makes it seep along the surface and becomes visible. I'm guessing the spring has 5+lbs of force at least. I suspect the upper o-ring is moreso to try and keep dirt/dust/grit from collecting beneath the surface, falling into the engine as soon as you remove it.

[@catinthehat5140]

Wouldn't any catch can suck oil from the PCV reservoir? I think you said in this video or another that you shouldn't install one but doesn't this apply to any PCV of this style?

[@datadrivenmqb]

I don't think catch cans work well with OEM PCV systems, and the few that do I think moreso is playing with timing of the one way valves opening and closing (basically dumb luck). The BMS CC seems to be one of the more consistently successful ones due to small can size and short hoses (less volume that vacuum must draw down from the TIP).

[@catinthehat5140]

@datadrivenmqb wouldn't any increase in tube length be an increase in volume and therefore increase crankcase pressure? Even if that's a small amount maybe over a long period it causes the rear main seal to deform enough to leak oil

[@datadrivenmqb]

@@catinthehat5140 That's the theory - I think a small can w/ short hoses like the BMS aren't really bad. The problematic ones are the ones with monstrously long hoses that will cause further obstruction of pressure escaping/being sucked out.

[@catinthehat5140]

@@datadrivenmqb What would be great is all the different situations and how the pcv reacts. Like "High load, Turbo not spooled = this happens, that happens" etc

[@francescopastino]

My PCV was making loud noises at startup which then i found caused my oil cooler to leak oil in coolant. I replaced that and i am going to do the pcv retrofit next so i dont have the issue again.

[@williambrown2869]

What if you do a reduction in hose volume to length of hose if length of hose is normally one foot now if you add another foot of hose plus catch can should get a 60% reduction in hose in and out opening. This might work with in line catch cans is my theory or better understanding untested hypothesis.

[@datadrivenmqb]

Hose volume definitely affects inline cans - I know of a few people who’ve changed their setups and gone from filling the can in. 3-4 autocross runs to hardly getting anything in the can after changing hose length and moving the can closer to the valve cover.

[@philpots3216]

I have just replaced mine on vw polo gti 6c, it has made a big difference to my idle and performance also no more smoke, i noticed though when car is idling if i take the oil cap of there is a strong vacuum and engine runs weird until i put cap back on, is this normal, its an oem part and has fixed my smoke and idle problem but im concerned about the vacuum when oil cap or dipstick is removed. Any feedback will be much appreciated

[@datadrivenmqb]

That’s normal operation of an OEM PCV system.

[@philpots3216]

@@datadrivenmqb you know you are the first reply I've had, can't thank you enough.

[@philpots3216]

@datadrivenmqb hello again, I subscribed to your channel,,,, I have another question, you said the strong vacuum is OK and is doing what it should, I noticed a small whistle on the diaphram and when I cover the small hole it stops,, this is a new part but I'm beginning to think it's faulty😀

[@datadrivenmqb]

@@philpots3216 yeah that does sound potentially bad. It might not be too much vacuum, but it’s sucking in unmetered air through a torn diaphragm. If it won’t cause warranty return problems, you can pop the cover off and check. FWIW I only ever recommend a 100% OEM from VW/Audi part. The non-VWAG parts are inconsistent quality at best.

[@philpots3216]

@@datadrivenmqb it is oem and only 2 months old, I'm going to send them a video and see if they will replace. There should be no suction (whistle)on the diaphram correct?

[@thomaspedersennorway]

Any reason for not upgrading the turbo bend?

[@datadrivenmqb]

You mean the turbo inlet pipe? I just have an IS20, no need for anything else IMO. Probably not absolutely necessary on an IS38 either.

[@thomaspedersennorway]

Yeah, the turbo inlet pipe 😊 okay, kinda see most people say it should be upgraded, so just different hearing someone using their car like you do and keeping things stock on that part of the turbo 😅

[@datadrivenmqb]

@@thomaspedersennorway yeah, I don't doubt there could be a SMALL gain from replacing it, but frankly I'm chasing a 2:10-2:11 lap time at VIR before worrying about adding more power. IMO keeping stuff closer to stock is the best way to ensure it stays reliable.

[@MichaelT-ft3cz]

Compatible with the 1.8l?

[@datadrivenmqb]

Yes. @Karstgeo72 is running it on his IS38 1.8T wagon. I don't know that I'd do the full retrofit on an IS12 car, but basic retrofit would be fine for a "stock replacement" equivalent. Check out some of the other videos on the PCV Playlist or at www.datadrivenmqb.com/mk8pcv

[@gatekeeperadf]

Have you heard that a PCV leak causing a thermostat housing leak. This is what I'm being told by the dealership. Any help is greatly appreciated.

[@datadrivenmqb]

No. Sounds like they don't know their asses from their elbows.

[@jayeddleston9486]

I remove the oil cap the car revs up.before and after I changed Pcv?? Cars burning oil

[@datadrivenmqb]

It's normal to idle differently when oil cap is removed - you're introducing an air leak. If the oil cap is lightly held in place by suction at idle as you try to remove it, that is normal.

[@philpots3216]

​​​@@datadrivenmqbhi, I've just replaced my pcv on my 6c polo gti, it has made my idle alot better also no more unwanted smoke via exhaust, I did a test and when I remove oil cap it now has a strong vacuum,, also when I pull the dipstick there is a mild vacuum, the engine tone changes until I put cap back on then returns to normal,, is the strong vacuum normal, its a new oem part, I'm just worried that vacuum is to strong, some say its showing the pcv is working as should, im just concerned because its very strong suction...

[@datadrivenmqb]

@@philpots3216 it’s a pretty strong vacuum, -1psi feels like a lot when it’s a large surface area like the oil cap. The only real thing that would allow excessive vacuum is if the diaphragm were stuck open AND not torn… which is basically impossible. You’d need to plug the external pressure reference port on top of the PCV valve while the car is OFF, and then start it up. The car would run real weird most likely and set fuel trim or running lean DTCs similar to when the diaphragm tears, along with a loud squealing from air being pulled past the crank seal. This is what happens on some other (non VW) cars when their PCV valves fail and pull excessive vacuum. Chevy Cruze 1.4T for instance I’ve seen fail like this.

[@bryanviper]

Wow this is pretty cool and something i may be interested in. I also autocross/track and used to get the smoke here and there years ago. Since then I have upgraded to the Audi S3 design on my 2016 Golf R and it has helped a lot, Dont think I have seen much smoke at all since then. Wonder if you have tested the S3 PCV? Either way hopefully you figure this out and there are some good benefits you may even try to sell a package with everything we need + instructions. I would consider it.

[@datadrivenmqb]

I have not tested it yet (the BL revision is what you're referring to right?). I have no interest in selling a package or anything. All the part numbers are listed in the video description (and video itself). You can walk into any VW dealer and order them, or online.

[@bryanviper]

@@datadrivenmqb Yes the 06K103495BL. CUrious how it compares to the VW Golf R version you tested. There may be an improvement.

[@datadrivenmqb]

@@bryanviper if I get my hands on one I plan on testing it. Currently working on getting an extra pin populated in my ECU so I can add another MAP sensor to go to the oil cap I made, so I can directly data log the crankcase pressures vs RPM/boost/etc. Should be much more accurate than videoing a mechanical gauge.

[@xKypQx]

I am having a smoke issue in my Golf 7R. I have replaced my AA rev. PCV Valve to BM rev., still the same problem. But tomorrow I am replacing for BL rev, so we will see.

[@xKypQx]

Changed for BL today. Did some fast corners, breaking, accelerating so far no smoke. I Keep my fingers crossed, but its looks like problem od solved

[@vgmgalileo]

Mk8 PCV is for 2.0l, so it will fit my MK7 1.8l?

[@datadrivenmqb]

Yes it should fit. I'm not sure I'd recommend the full retrofit on an IS12 since that's a tiny turbo... but basic/full retrofit will physically fit. @karstgeo72 did the swap on his IS38 1.8T Wagon.

[@Elia__music]

❤️❤️

[@thomasdeir6212]

Subbed!

[@eurosurgeonjoe2700]

Has anyone tested and confirmed this solves the smoke cloud under heavy braking and decal on track? Got black flag for the thick smoke cloud today and almost lost my points - prefer not to keep happening

[@datadrivenmqb]

I will be at Summit Point at the end of the month for Fastivus, so will report back then! There is someone else in one of the FB groups who has done the retrofit and claimed it was successful on track, though I don’t know if his details/car specs/etc.

[@datadrivenmqb]

@eurosurgeonjoe2700 to follow up: No issues at Summit Point on the Shenandoah circuit and then again no issues over 3 days at VIR for Oktoberfast. I have info from both trips here: www.datadrivenmqb.com/tripreports

[@Cjensen363636]

@Cjensen363636 26 minutes ago Great explanation, I was always wary of catch cans (and I ran one briefly on my Mk 6). I’m curious about the results if anyone tests it with an intake and turbo inlet pipe. It was great meeting you at VIR in July, I learned a lot and are planning a few track days next year there.

[@datadrivenmqb]

Glad it was able to help! I have some more stuff planned to test in the future, I'm probably a couple weeks away from adding another MAP sensor specifically for the crankcase so it can be logged and overlaid directly (as opposed to taking video of a physical gauge). Hope to see you at VIR again! I'll be back with TSCC in December!

[@catinthehat5140]

Someone made a video where they compared catch can crankcase pressure. Some of them caused a massive increase.

[@TheObiwantoby]

Just performed this. I suspect might have a marginal effect on any carbon buildup. In theory.

[@datadrivenmqb]

I don't think the basic retrofit would have much effect, though there's a small chance that the full retrofit with an 034 TMD plumbed to the Venturi may help. Several people have reported cleaner exhaust tips with the full retrofit. Check out the other videos in the PCV playlist for the one on the Venturi being used.

[@StanBenton]

Damn

[@philip6106]

Put thicker oil in the problem then watery oil

[@datadrivenmqb]

Oil is definitely not the problem. My car has run 5w40 ever since I bought it for reference.

[@DevineDigital]

This is not Excel, are you even really a chungus? 🤦‍♂️how can I believe you without excel!

[@datadrivenmqb]

I resorted to Excel's cousin - PowerPoint

[@DevineDigital]

@@datadrivenmqb 🤣I approve!

[@slimlou]

@@datadrivenmqb😂

[@datadrivenmqb]

@@slimlou ah yeah there's a backstory... Me and @DevineDigital are in a tuning chat together. My username there was originally "derhase" or "the rabbit" in German. As a joke I changed it to "der große chungus" and it stuck. After the PCV video it evolved into "Professor Chungus". 😂