I am going to make a test rig for boost/vacuum leaks.

Can I disconnect the famous L shaped hose (running to the air pump) and place my test rig in there, without having to cap off the PCV valve? Will it push oil?

My idea is to have a hose that fits where the L hose is, and my hose will have a tee T in the middle, with P gauge, a valve and pressurizing port - planning to use small tire inflator.

Talking about 1.8 T, 2001

 

Have you seen this?

http://audizine.com/forum/showthread.php?t=64411

 

but i thought the L hose is easier to remove.

 

The TIP is easy enough to remove from the air box. I have used this test a few times with good results Just dont overpressurize the system.

The one problem with a small pump is that the flow is insufficient, so its very hard to pressurize the system. Atleast thats what I have heard.

 

yea, a 12v or bike pump probably wont flow enough and it will be too loud to hear any leaks over the pump running. an air compressor with a tank is almost necessary.

 

still the question: do I have to block off the pancake valve if I am pressurizing through the L hose? My issue is the hose size, I can build a small, 1/2 or 3/8 hose with a tee and all fittings, but going to the airbox I am to 2-3" hose and all the reducers and bushings etc. in that size range add up to the cost of the whole thing.

 

all you need is a tennis ball, you use the clamp that connects the TIP to the airbox to make a seal around the tennis ball, and two small holes in the ball to get air into the system

i dont know exactly what L-hose you are talking about, the breather systems are slightly different for the different engine codes, i think

 

Will do it this way
http://www.a4mods.com/index.php?page...tml&category=5

which is "tennis ball method" in essence

 

I saw this note on another post somewhere. Is that important/applicable to the A4 B5 as well?

IMPORTANT: In order to perform the pressure test, it is
very important that you disconnect the PCV return
hose from the TIP. This WAS NOT written in the
writeup I was following.....
what happens is that after the system is pressurized,
oil comes back down the pcv pipe into the TIP...and
hence the turbo....you will end up with blue smoke in
your exhaust.....in order to stop this you have to
disconnect the check valve for the PCV return line and
plug the hole
I used a rubber wine bottle cork and a hose clamp to
plug the hole

 

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I saw this note on another post somewhere. Is that important/applicable to the A4 B5 as well?
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Yes, it is. I did exactly what you copied here. Even then, I could still hear air going through oil somewhere in the engine. But I did find leaks this way, now I am at -23" vacuum coasting in gear with gas pedal off and I have about 16-17 psi with my APR 1 chip.