Intake Valve Cleaning

[sleepyS3]

My 2016 S3 is about to hit 100k kilometres. I’ve been thinking about walnut blasting the valves for some preventative maintenance. No rough idles or misfires. Is it worth it or am I wasting my time?

[ReggieNoble]

If it has never been before, then it's definitely worth it!

[MikTip]

My 2016 S3 is about to hit 100k kilometres. I’ve been thinking about walnut blasting the valves for some preventative maintenance. No rough idles or misfires. Is it worth it or am I wasting my time?

You will know the second you remove the intake.

Or figure out a way to use a borescope to see the valves without removing the intake.

I can tell you my valves were very badly carbon covered....as well as the intake...

[S3_Miles]

You will know the second you remove the intake.

Or figure out a way to use a borescope to see the valves without removing the intake.

I can tell you my valves were very badly carbon covered....as well as the intake...

Im considering this myself (60k miles, so roughly the same as OP). Questions specific to you @MikTip
A) Did you have any indications you should do it? (misfires and such), or just preventative and found it when removing the intake?
B) How many miles (if you remember) were on your car when you did it?
C) Do you live where there are temperature extremes, especially cold? (I heard cold environments only accelerate this issue)

Thanks!

[MikTip]

Im considering this myself (60k miles, so roughly the same as OP). Questions specific to you @MikTip
A) Did you have any indications you should do it? (misfires and such), or just preventative and found it when removing the intake?
B) How many miles (if you remember) were on your car when you did it?
C) Do you live where there are temperature extremes, especially cold? (I heard cold environments only accelerate this issue)

Thanks!

A. Miss fires yes. Found two bad fuel injectors so removed the intake to change the injectors. Looked into the intakes...seen allot of carbon!



B. 150,000

C. What accelerates the issue is the PVC/Oil separator goes bad, and or allows too much oil fumes to be sucked back into the motors intake pipes.
VW/Audi engineered the E888 engine to suck back into the intake its oil fumes in an effort to burn them in the combustion chambers. However allot gets stuck to the
intake and valves. The hose on the turbo inlet pipe is where the oil fumes enter the intake. Its why theres oil in the intake. Its why valves get carboned. A poor design.
European S3 have the second row of injectors to reduce the carbon/oil fumes on the valves. US models dont have the extra injectors.

If you can...pull the MAP sensor on to of the intake and route a borescope into the intake to see how much they are carboned. Especially #2 intake valves.

This way it can be inspected without removing the intake.

[S3_Miles]

Fantastic reply! and great insight.

Curious about one thing -

"What accelerates the issue is the PVC/Oil separator goes bad, and or allows too much oil fumes to be sucked back into the motors intake pipes.
VW/Audi engineered the E888 engine to suck back into the intake its oil fumes in an effort to burn them in the combustion chambers. However allot gets stuck to the
intake and valves. The hose on the turbo inlet pipe is where the oil fumes enter the intake....."

Maybe I am obtuse but could I not simply disconnect this hose, block off the turbo inlet orifice and put a remote air filter of some sort on the end of the hose? This way oil fumes go no where but through a filter / collection of sorts.

By example, I also ride a motorcycle, and the particular one I have has a crankcase hose vent into the airbox. The common thing to do since the motor (a 1,301 cc v-twin) has so much crankcase pressure it can push oil up into the intake.....is to disconnect that hose from the airbox and just put it on its own breather, and block the airbox hole off.

If it could potentially slow this issue, I would rather do that then risk the outcome. I get why they are trying to get the oil fumes to burn....cleaner air, efficiency, etc...but as you know most things that help the environment are counter-intuitive to a ICE design for best result.

[MikTip]

Fantastic reply! and great insight.

Curious about one thing -

"What accelerates the issue is the PVC/Oil separator goes bad, and or allows too much oil fumes to be sucked back into the motors intake pipes.
VW/Audi engineered the E888 engine to suck back into the intake its oil fumes in an effort to burn them in the combustion chambers. However allot gets stuck to the
intake and valves. The hose on the turbo inlet pipe is where the oil fumes enter the intake....."

Maybe I am obtuse but could I not simply disconnect this hose, block off the turbo inlet orifice and put a remote air filter of some sort on the end of the hose? This way oil fumes go no where but through a filter / collection of sorts.

By example, I also ride a motorcycle, and the particular one I have has a crankcase hose vent into the airbox. The common thing to do since the motor (a 1,301 cc v-twin) has so much crankcase pressure it can push oil up into the intake.....is to disconnect that hose from the airbox and just put it on its own breather, and block the airbox hole off.

If it could potentially slow this issue, I would rather do that then risk the outcome. I get why they are trying to get the oil fumes to burn....cleaner air, efficiency, etc...but as you know most things that help the environment are counter-intuitive to a ICE design for best result.

I have this:

https://www.goapr.com/products/engin..._-_mqb_18t_20t

[S3_Miles]

I have this:

https://www.goapr.com/products/engin..._-_mqb_18t_20t

Thank you! I am obtuse (slaps forehead). I now understand what a catch-can does for our cars (never took time to find out). Going to invest in one asap lol

[texasboy21]

Fantastic reply! and great insight.

Curious about one thing -

"What accelerates the issue is the PVC/Oil separator goes bad, and or allows too much oil fumes to be sucked back into the motors intake pipes.
VW/Audi engineered the E888 engine to suck back into the intake its oil fumes in an effort to burn them in the combustion chambers. However allot gets stuck to the
intake and valves. The hose on the turbo inlet pipe is where the oil fumes enter the intake....."

Maybe I am obtuse but could I not simply disconnect this hose, block off the turbo inlet orifice and put a remote air filter of some sort on the end of the hose? This way oil fumes go no where but through a filter / collection of sorts.

By example, I also ride a motorcycle, and the particular one I have has a crankcase hose vent into the airbox. The common thing to do since the motor (a 1,301 cc v-twin) has so much crankcase pressure it can push oil up into the intake.....is to disconnect that hose from the airbox and just put it on its own breather, and block the airbox hole off.

If it could potentially slow this issue, I would rather do that then risk the outcome. I get why they are trying to get the oil fumes to burn....cleaner air, efficiency, etc...but as you know most things that help the environment are counter-intuitive to a ICE design for best result.

Simply running a filter/venting to atmosphere allows the block to become pressurized causing more problems.

A catch can (or properly running PCV system) keep the block in a vacuum. This keeps fresh air flowing through the passages no matter if the turbo is creating positive boost pressure or not.

[XMetal]

Thank you! I am obtuse (slaps forehead). I now understand what a catch-can does for our cars (never took time to find out). Going to invest in one asap lol

Be careful of the type of catch can that you install - see the video below. I would prefer to get one that utilize the OE PCV rather than replacing it altogether.

https://www.youtube.com/watch?v=va7nnO-YuMg

[MikTip]

Be careful of the type of catch can that you install - see the video below. I would prefer to get one that utilize the OE PCV rather than replacing it altogether.

https://www.youtube.com/watch?v=va7nnO-YuMg

The above PVC plate has no oil baffle like the Raceingline or APR or RS3 LMS PVC plate has. Which is key for it to work properly on the E888.3 Its also an older Mark 6 version plate.

I have heard people have issues with the CTS's version/type in the above video.


I have run Racingline and APR's catch cans. Zero issues on my E888.3 motor.

The issue with the OE PVC is its plastic and its diaphragm breaks and you cant see it then it allows excessive oil fumes into the intake causing carbo build up much faster.



The factory Audi LMS RS3 race car uses a similar all metal top plate as APR and Racingline.



Whys the factory race car have a metal PVC??? Hmmmm...


The LMS catch can is hidden back behind the motor and it drains oil back into the oil pan with a check valve.

While catch cans help...they dont totally eliminate carbon build-up...reduced amounts of oil fumes are still sucked into the motor.

The metal PVC plate wont fail. Its all metal and has no moving parts. It also gladly accepts higher than stock boost levels from Stage 1 and Stage 2 tunes.

[MikTip]

DBV2's 700HP S3.

APR catch-can.

[XMetal]

Draining oil fumes back into the oil pan with a check valve seems more logical than letting it go into the turbo inlet to burn it off. I wonder what's the logic behind letting it (oil fumes) burn off in the combustion chamber instead of draining it back into the oil pan?

Did not know about the LMS catch can. I need to ask my indie (who owns several LMS cars and races in the series) about it the next time I visit them!

[MikTip]

Draining oil fumes back into the oil pan with a check valve seems more logical than letting it go into the turbo inlet to burn it off. I wonder what's the logic behind letting it (oil fumes) burn off in the combustion chamber instead of draining it back into the oil pan?

Did not know about the LMS catch can. I need to ask my indie (who owns several LMS cars and races in the series) about it the next time I visit them!

Factory VW/Audi engineers who designed the E888 for the street and emissions...

The E888.4 has some revisions to the oil fumes/pvc system which involve the balance shafts sucking oil fumes back into the motor vise going into the intake as much.

When I drain my catch can...it has allot of water in it so the oil in it looks like chocolate milk...

It would be nice if APR or IE developed a catch can that drains back into the pan.

They probably offer that for the serious track racers. $$$$

034 talks about it in their videos...but dont see them selling one on their website.

[S3_Miles]

Simply running a filter/venting to atmosphere allows the block to become pressurized causing more problems.

A catch can (or properly running PCV system) keep the block in a vacuum. This keeps fresh air flowing through the passages no matter if the turbo is creating positive boost pressure or not.

Thank you. Appreciate the knowledge.

Be careful of the type of catch can that you install - see the video below. I would prefer to get one that utilize the OE PCV rather than replacing it altogether.

https://www.youtube.com/watch?v=va7nnO-YuMg

Great video and makes complete sense