Pressure in crankcase (1.4 TFSI EA211)

[Jussi23]

Hi all,

The car in question is a 2014 A3 with a 1.4 TFSI engine.

Lately the engine has started to consume more and more oil so I started investigate the cause.

With the engine running I took the oil filler cap off and pressed my hand against the hole. There is definitely pressure instead of suction from the crankcase, so I'm assuming the PCV system is clogged somewhere.

Any suggestions how to find the blockage?

Apparently these newer TSI/TFSI engines have an integrated PCV system instead of one that you can just bolt off and put a new one in.

So, what should I do next?

 

[northpole]

you remove it and replace it.... this here is the PCV valve for your engine

 

[Jussi23]

you remove it and replace it.... this here is the PCV valve for your engine

Thanks for helping out!

That's what you would do in most cars but these newer EA211 TSI/TFSI engines the PCV is integrated into the block. This self-learning material explains it quite well from page 10 onwards:
https://static.nhtsa.gov/odi/tsbs/2015/MC-10124696-9999.pdf

I did some testing to find any blockages or sticking one way valves. The fresh air valve on the top of the engine is fine as is the passage from crankcase to the valve at the turbo. I could not get a good enough grip on the pipe between the oil separator and intake manifold so I could not verify if the valve in the manifold is working or if the feed from the oil separator is clogged.

There was a coat of sandy oil on the oil filler neck and at the turbo where the breather hose is attached so possibly minor air leaks there. Cleaned up well to see how quickly it will build up again. Don't think enough oil would escape from those spots to even notice it between oil changes.

Any other things I should check?

 

[northpole]

than you'll need to check the bottom part of it there is another non return valve just above the sump.... but in most cases an oil flush should remove any blockages, so if it was my engine i'd just run an oil flush like the one from STP and i'd double the running time, than put in fresh oil and oil filter to see if the problem is gone a good drive should tell yo soon enough if it's still a problem...

that said if the bottom part of the PCV is acting up it can be replaced to it's just a PITA to do so. and yes that part is also found on eBay

 

[Jussi23]

than you'll need to check the bottom part of it there is another non return valve just above the sump.... but in most cases an oil flush should remove any blockages, so if it was my engine i'd just run an oil flush like the one from STP and i'd double the running time, than put in fresh oil and oil filter to see if the problem is gone a good drive should tell yo soon enough if it's still a problem...

that said if the bottom part of the PCV is acting up it can be replaced to it's just a PITA to do so. and yes that part is also found on eBay

That's true about using some sort of motor flush to get rid of some of the crud and sludge, I've been considering that option. Now would be the time to do it before the build up gets too bad and the risk of dislodging something big that will block a critical oil path is too much.

I don't think there is a non-return valve down low though. There is one at the bottom of the intake manifold but there just wasn't enough space for me to unplug the hose. I wanted to blow some air through to see if the valve is open or not but just couldn't get there.

 

[northpole]

I don't think there is a non-return valve down low though. There is one at the bottom of the intake manifold but there just wasn't enough space for me to unplug the hose. I wanted to blow some air through to see if the valve is open or not but just couldn't get there.

look at the pdf you linked again than read the section starting on page 10 all the way down to page 11 ( if you open it with your browser it'll be page 14 and 15)... you'll find there is another non return valve.. I thought it to be a bit much and cause for problems... but hey that's how they designed it.

 

[Jussi23]

look at the pdf you linked again than read the section starting on page 10 all the way down to page 11 ( if you open it with your browser it'll be page 14 and 15)... you'll find there is another non return valve.. I thought it to be a bit much and cause for problems... but hey that's how they designed it.

Ok maybe I'm blind or just misunderstanding but I read that section again and there are three non-return valves. One on the top of the valve cover next to the oil filler, another one on the turbo and a third one at the bottom of the intake next to the throttle butterfly valve. The oil separator does not have any valves.

Or maybe the one on the intake is the one you are talking about? That's the one I couldn't get to because there wasn't enough room.

 

[northpole]

nah you got them all then... i'd still just run an oil flush as i said before it's the quickest way of getting any sludge buildups and blockages removed from the system... just follow the instructions but double the working time to get better results.. I always do it that way, and it has never caused a problem