Pressure Testing Turbo Hoses.

[jm-baker]

I tryed pressure testing the hoses on my S3 today.

I made a 80mm plug, put a shrader valve in it, and put it on the inlet hose, where it connects to the MAF.

I then removed one of the hoses connecting to the inlet hose (the larger of the two) and plugged it off. From what i can see, this hose i removed is the breather hose for the engine, as it connects back to the top of the head ?? The smaller of the two i left attached ( goes too vent side of N75 valve).

When i apply pressure i can hear what sounds like oil bubbling in the sump, as if air is leaking back into the engine. Tho i can see no other route it could get there other than the hose i plugged off.

Any ideas ??

Any help would be much appreciated!!

I cant seem to find a good write up on how to do a pressure test, and i have no manual to refer too.

Cheers

 

[Jamesh]

Had this saved in my favorites keep meaning to build one.

http://forums.audiworld.com/a4/msgs/1659806.phtml

 

[jm-baker]

Thanx 4 the link, iv not seen that site before.

Reading it, it seem to be exactly what i did today, so im not sure why i can hear the bubbling inside the engine when i add pressure??

 

[dummi]

when you say after the MAF , did you mean after the turbo? the intake does have breather pipes into it.

 

[jm-baker]

No, after the MAF. I took the hose off the MAF meter and put my test plug with valve in at that point.

The two hoses i then refer to are the two that tee off that hose, before it goes onto the turbo.

James

 

[jm-baker]

Been thinking about this more, could the pressure be going through the turbo bearings and into the oil lines some how? i really want to get this pressure test done.....

 

[dummi]

if your bearings seals are gone yea , you'd also be getting oil leaking into your turbo and being blown through the exhaust.

 

[Jamesh]

Just a thought did you block off the pipe that goes to the throttle body, it could be leaking through TB butterfly or through the idle control valve.