Thread: URO Parts AOS
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Old 12-15-2016, 10:55 AM   #1
ksboxster
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Join Date: May 2016
Location: Kansas
Posts: 16
URO Parts AOS

Looking for similiar experience with an unusual AOS problem. ?

I bought the URO Parts air oil separator to replace my original one about 3 months ago. It seemed to work fine for a short while, but now it isn't. The problem is NOT the usual membrane failure however. Usually with a worn AOS there is TOO much vacuum pulled on the crankcase, and you have all the usual worn AOS symptoms.

The membrane/diaphragm is supposed to modulate the vacuum, allowing a small part of the intake vacuum to pull on the crankcase so you have negative pressure.

In my case, the new one I installed is not pulling ANY vacuum on the crankcase. Zero. It is like the diaphragm is stuck closed. I checked both ventilation hoses (from the driver side head, and from the AOS to the throttle body), both are fine. But I definitely have slight positive crankcase pressure. When I open the oil cap in the trunk I can see that. And the AOS vent valve/pressure relief over on the driver side head is popping off, getting oil all over everything. That's how I figured out that I had a problem - trying to find where the oil leak was coming from.

So, I ordered the Porsche AOS and I'll install it over the holidays. While I'm in there I will try to diagnose why the URO parts AOS failed.

One more strike against the URO parts AOS...
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