I've got a 2010 turbo (997.2), checked for boost leaks and the car did not hold any pressure.
To pressurize the system I connected to the lower intercooler hoses.

The air is coming out of the air oil separator line that dumps back into the intake.

If I pull the line in the below picture and plug that port on the y-pipe it holds pressure.
The hose that connects to the port is called "Ventilation Pipe Crankcase" ( 9A110754074 ) in the Porsche parts diagram.

Is this normal? I'm wondering if there's a check valve or maybe an electric valve that closes when there's boost?

Thanks!!

 

I'm currently in the same process. Can't help much as mine was leaking immediately out of the passenger side diverter valve. I did get 20 psi in the system (maybe 15-20 seconds before leaking back to zero) and the only leak I heard was through the diverter...so far.

 

What leak "kit" are you guys using?

 

This is the kit I got. https://turboboostleaktesters.com/po...ster-shop-kit/

 

Thanks Vette2viper, that does help some. The fact that it takes 15 to 20 seconds for your's to leak back to zero shows that somethings really wrong with my car.
I'm going to go back and remove the diverter from the intake pipe it's mounted in while leaving the other two hoses attached to make sure there's nothing going on there.

Stilov, I'm using the homemade ABS pipe version to test. Looks similar to what Vette2viper is using but not near as nice.

 

You can do on your own with some PVC, glue and a compressor fitting.
Check post #8 : https://www.6speedonline.com/forums/...7-1-turbo.html

 

OP did you figure out what's going on?

 

Yes, I believe so.
When I pull the hose off (arrow pointed at the hose location in my first post) that Porsche calls "Ventilation Pipe Crankcase" and plug where the hose connected to the y pipe, the system holds pressure.
I followed the "Ventilation Pipe Crankcase" hose and it connects to a port near the back of the block, there's no check valve.

It appears that you need to disconnect that hose and plug it's port on the Y-pipe to check for boost leaks on this engine.

My friend has 2010 Turbo as well and we noticed the same on his.

 

Saw the same thing on mine today.

I had initially thought my leak was coming from either the DVs or the air/oil separator but come to find out it's at the same place as yours.

It seems counter-intuitive to have boost pressure pumped into the crankcase.

 

thread resurrection... I am experiencing similar....

I thought it was the DV, but pulled them and they seem to crack open at about 15psi when you pull vac on the little port.

pressurized the intake at the intercooler inlet hoses, but i hear a leak that sounds similar in placement to OP's situation.

Do you have a diagram showing which other part should be plugged to do a boost leak test?

 

So I reread. I plugged the nipple of the y pipe that goes to the pcv and it holds way better obviously. Lol!

Here is the curious part.... this is a new hose and it seems like the material is permeable.

Anyone ever seen this before?

 

Glad you figured it out.

I had the same issue on a friends car (mine is in storage). He decided to order that piece to see if the new one will bubble like yours.

 

Maybe not as having a pressurized crankcase would reduce the pressure differential across the piston rings to reduce blowby. If the crankcase was at atmospheric pressure then any vapour there could not get into a boosted pressurized intake system as the pressure differential is in the wrong direction.

When there is no boost and intake at vacuum then the pressure differential would allow crankcase vapour into the inlet air to engine for combustion.

 

I have the same Problem , but idont undertand what you mean ? can you say it in a different way ?