An inexpensive way to test for a bad AOS

[logray]

An inexpensive way to test for a bad AOS

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There are a lot of indicators for a bad Air Oil Separator. 1. Excessive white smoke out the tail pipes. 2. Excessive vacuum on the oil filler cap, making it very difficult to remove, and once it is off the engine idle will become very rough and might stall. 3. Excessive oil in the tube leading from the AOS to the plenum behind the throttle body, and even excessive oil in the intake plenum. (a light film of oil is considered normal) 4. High pitched screeching noise from the AOS unit itself.

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• Author
  logray
• Category
  Carrera (996) - Common Fixes and Repairs
• Submitted
  08/28/2011 09:40 AM
• Updated
  04/30/2013 09:26 AM

 

[kbrandsma]

I recently used your DIY and created my own AOS tester. Here is a shot of an adapter attached to my oil cap.

Here are two photos of the air tube with one end attached to the oil cap and the other to the gauge.

I marked the start and then the finish after opening the valve to the oil cap.

Here s a short movie clip of activating the valve by the oil cap.

Edited October 3, 2011 by kbrandsma

[logray]

Awesome! Great job. Now you know your crank case vacuum is normal and AOS good. :)

[Johnny-5]

This is the support topic for the DIY Tutorial An inexpensive way to test for a bad AOS. Please post here if you have any questions or feedback.

You rock thanks for link. Ill probably build one later on this weekend and see test the vacuum in the system.

[kbrandsma]

Deleted - accidently posted on the wrong thread.

Edited June 20, 2014 by kbrandsma