2.0T TFSI Gen II CDNC Valve stem seals question

[doublespeeded]

Hi all,

I’m wondering if anyone could share some light as to whether valve stem seals failure for the 2.0T is a known/common problem for this engine and at roughly what mileage?

The reason I’m asking is that I believe mine may be shot at 77,000mi. And pretty much showing most of the symptoms with smoke.

Thanks in advance






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[Theiceman]

almost nil .. in fact in the years i have been on this forum i have NEVER heard of it....

problem we seem to have is rings and PCV

[FR_A4]

Probably not the stem seals.
At 155k the kids A4 showed some leakage on one of the valves. Just one. It was sort of evident as the carbon build up on that valve was near the top of the valve.

[Smac770]

I don't know anything about valve stem seals. If you remove the PCV from the cylinder head cover and remove the tube to the intake manifold and throw smoke into that intake manifold opening or into the front 02 sensor opening, one should not see any smoke out of the PCV opening, right? Or are the stem seals a dynamic thing that are loose cold and sealed hot?

[doublespeeded]

I don't know anything about valve stem seals. If you remove the PCV from the cylinder head cover and remove the tube to the intake manifold and throw smoke into that intake manifold opening or into the front 02 sensor opening, one should not see any smoke out of the PCV opening, right? Or are the stem seals a dynamic thing that are loose cold and sealed hot?

Thanks all for your replies.

I’ll have to get this checked out professionally very soon by a mechanic. Ive been though a bit of a bump road with this car in the past year.
So I take it that it could also be faulty PCV valve can cause excessive burning of oil?

Here are the symptoms I’m experiencing:
• Only white smoke (definitely not coolant)
• Only happens if I let it idle for 1.5 – 2 minutes in (N)eutral or (P)ark. (never happens whilst driving or idling in (D)rive
• Very occasionally it may occur upon a cold start up

But in saying that, it doesn’t produce smoke in on downhill deceleration which is normally present with bad valve seal.
I don’t think it’s a Cylinder head, piston ring or head gasket as those normally cause oil consistently.
The Turbo/K04 that’s equipped is around 12,000 Miles, so I don’t think it’s a turbo hot seal. But - I did have a bad blockage in the exhaust, which could’ve potentially damaged the turbo or valve seal)

The PCV I have is also around 12,000mi , replaced at the same time with the turbo.
But – the ECS tuning catch can I installed earlier in June 2020, this symptom seems to have happened since then. Which their catch can works with the PCV valve (not removing PCV as opposed to other designs). I’m also wondering if the vacuum on this design has degraded the PCV, Stem seals or even being the sole cause of pressure coming back pass.

https://www.ecstuning.com/b-ecs-part...004136ecs01kt/

Perhaps the first step would be to reverse the catch can and see if that improves the issue. But I may have lost the two bolts for turbo vent and the ECS bolt is longer.
or ill just have to pass it to the workshop and get them to do a leak down test etc

[old guy]

You need to remove the ECS catch can. Even though the ECS catch can leaves the PCV in place the PCV no longer functions as a crankcase breather. Once you block off the connection to the intake manifold you no longer have a purge air function that allows the block to operate under a slight vacuum. Without the connection all the PCV does is provide a blow-off function to the turbo inlet port.

And to make matters worse the PCV combi valve requires a little over 2 psi of pressure before it opens and allows flow to the turbo inlet port. So essentially you are pressurizing your block whenever you are steady state driving. You would be better off with a PCV block off plate like the CTS design (not that I am recommending running any catch can).

By operating the block under a constant positive pressure you could be forcing oil through the valve guide seals.

EDIT: Didn't we already discuss this a few months ago? Clicky click®

[Theiceman]

Oh its the rings lol

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[doublespeeded]

Oh its the rings lol

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well don't you think that's irony? Audi uses rings as its logo, and their rings caused a big portion of their cars to be lemons? lol

You need to remove the ECS catch can. Even though the ECS catch can leaves the PCV in place the PCV no longer functions as a crankcase breather. Once you block off the connection to the intake manifold you no longer have a purge air function that allows the block to operate under a slight vacuum. Without the connection all the PCV does is provide a blow-off function to the turbo inlet port.

And to make matters worse the PCV combi valve requires a little over 2 psi of pressure before it opens and allows flow to the turbo inlet port. So essentially you are pressurizing your block whenever you are steady state driving. You would be better off with a PCV block off plate like the CTS design (not that I am recommending running any catch can).

By operating the block under a constant positive pressure you could be forcing oil through the valve guide seals.

EDIT: Didn't we already discuss this a few months ago? Clicky click®

Appreciate the feedback old guy.
As mentioned, I’ve had a bit of undesirable occurrences with this car for the past year.
What occurred last time, was a leak from the upper timing chain cover, that was leaking oil on the top of the head. Which I have since had rectified at the mechanic workshop. At the time, he did mention that front cover/seals don’t hold the pressure and if the catchcan did raise the crank case pressure, it wouldn’t of been the cause of this particular cover.

I did notice something else change since then, aside from this Neutral/Park mode idling smoke getting worse. Previously, at the beginning, the ECS catch can seem to have caught moisture vapor, an orange watery substance. But as this smoke issue became noticeable, it no longer caught anything.
So do forcing through the Valve guide, do you think this would’ve cause any damage anywhere? Or perhaps damage and require a replacement of another PCV?
Don’t worry, it is a very good reason now to reverse/remove it. Its not all bad for me to put forward more info regarding this. As the info on this particular product is lacking and essentially have proved in the field that it simply doesn't work and what people should be steering clear of. Ill also report back of the findings once its removed, as this could potentially help others.

you wouldn't happen to know the part number of the two Allen key bolts for the turbo vent?

[Smac770]

What's a turbo vent?

[old guy]

Are you referring to bolt #16? Clicky click®

The first thing I would recommend is to remove the catch can and see if everything settles down. Next step would be to replace the PCV.

[doublespeeded]

Are you referring to bolt #16? Clicky click

The first thing I would recommend is to remove the catch can and see if everything settles down. Next step would be to replace the PCV.

Ok I’ve managed to find the two bolts in question (w/built in washer), Yes the #16.
Although, the existing ones look different to the ones on the parts layout page.

Anyhow, I plan to do the catchcan removal in the upcoming weekend.
But just looking it now, I’m wondering if I can just customise a short braided stainless steel hose equipped with x2 female -10AN (to join the turbo to the PCV); keeping the two billet Aluminum ECS made adaptors. (They both look pretty well made) and it will save me a slight bit of hassle of using these bolts & that OEM part aluminum/part plastic hose. (The two bolts/turbo is in a pretty awkward location and recall the lower bolt being a bit of a pain in the ass)

What do you reckon?
My only thoughts are, the braided hose is possibility a little narrower on the internal dia.
And also, I won’t know how long a braided hose will last.
Even though the OEM tube looks super flimsy, generally they are intended to last most of the life of the vehicle.

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[old guy]

Yes that should work just fine.

[doublespeeded]

Yes that should work just fine.

Heya Old guy,

I've had the the ECS catchcan removed for about a week and used the car to commute.
I am pleased to advise that there is no longer any smoke, at all!

I guess its now safe to say, from my experience, let this be a warning to all that this product does not work.

So it looks like the crankcase pressure build up, did cause the oil to flow past the Valve guide.

Do you reckon that ordeal would've weakened anything prematurely?

I'm now wondering if i should re-instate the 034 catchcan that i had on for years. But i recall there was a good write up (possibly on this forum) on whether these PCV delete type catchcans really help with GDI blow by. or if they can potentially make things worse, by pressurising the Crank case to some degree and allow some more oil to pass down the valves (rather than out the valves/piston/exhaust)?

I really appreciate your help and helping me resolve a bit of a headache. owe you one!

[old guy]

Glad to hear that you got it sorted out!

If you are no longer seeing any smoke you should be OK with the seals.

My personal opinion is that you are better off in the long run maintaining the OEM block breathing system. The typical catch can setup removes the purge air flow and essentially becomes a scrubbed blow off valve for the block.

A catch can can slow down the carbon build up but it doesn't eliminate it. Unfortunately as you found out catch cans can also introduce other unwanted issues.

[RPMtech147]

Just did a head job on one and the valve seals were nice and pliable after 110,000 miles 11 years old.