Kirk

... so I built myself this boost leak tester based off of info on the A4 forum (see link below) and hooked it up based off the instructions. When I pressurize the intake system I hear bubbling... which I think is my oil. This happens at low pressure like 6psi or so.

Any idea what this bubbling is? Is this normal? Is something broken?

Kirk<ul><li><a href="https://forums.audiworld.com/a4/msgs/1659806.phtml">Link to homemade boost leak tester</a></li></ul>

Brent V

Pressure on the intake side of the turbo will force air down thru the crankcase ventilation system.

I made my tester out of an old regulator and some pneumatic fittings so I can plug in and dial the pressure into exactly one bar. Then I just hook the other side of the regulator to a 2" PVC cap with a brass barb in the side. if all you hear is bubbling then you're prolly fine. Wiggle all your vac lines while you have the pressure hooked up as sometimes you'll only get a hiss out of them if you wiggle them.

Brent V

That I tried pressurizing the system with a pump action bike tire inflater too and it worked like ***. Much better to have an 80psi tank pressurized and hooked thru a regulator to meter a steady even flow of 1bar pressure.