RWPinNC

A friend who is not active on the web has a frustrating problem with his 1997 Boxster. The car has about 60,000 miles, Tiptronic, but with an aftermarket supercharger. Car has run beautifully for several years. About 2 years ago the AOS failed and was replaced with a Porsche part along with all AOS hoses. At the time the hoses seeped a little oil, but nothing significant. Now, with less than 1,500 miles added, the AOS has failed once more. His mechanic replaced it once again with a Porsche part, and the oil seepage has continued to occur. The mechanic, who is knowledgeable, is baffled and the owner is frustrated. We have speculated that the supercharger may be creating excessive crankcase pressure, and we might expect this on a 100k + engine. Can anyone shed light on possibilities.

Grasping at straws, if the pressure will continue to cause AOS failures, is there a potential solution in installing a traditional PCV valve and a catch can?

Quadcammer

I had popped an AOS on the track. I replaced it, but couldn't stop the car from smoking. Turns out I had about 60psi of compression in one cylinder, thereby heavily pressurizing the crankcase. I'd do a compression test as a first step.

The Radium King

aos vents to the intake. works fine on a normally aspirated car. on a forced induction car, aos cannot vent due to the pressurised intake. check; there may be a\n aftermarket checkvalve valve on the aos vent to the intake that stops the supercharger from pressurising the aos and let's the aos vent at idle when the supercharger is bypassing. or maybe not.

Macster

Has this:

https://www.pelicanparts.com/More_In...07-047-51-M100

been replaced?

(There is a separate o-ring that should be replaced as well.)

The part pictured serves in some way as a PCV. If this doesn't work right the AOS gets over pressurized which can rupture the diaphragm.

RWPinNC

We learned about this part yesterday. Next step will be to replace it. New AOS does not appear ruined yet, so fingers crossed. Thanks.