Beachproducer

Quick question for the more well-versed in all things M97…

I had the AOS replaced about a year ago… Last month I replaced my air filter and discovered oil in the intake plenum.

After the AOS has been replaced, should that still happen?

Optionman1

@Porschetech3 Can you help with this? FYI, he invented the UAOS, a better option when replacing stock AOS.

Porschetech3

All engines have a certain amount of blow-by. A good healthy engine will have 12-13 Liters per Minute at idle, and less than 70-80 LPM at full throttle...

Here is a simple easy to do test https://rennlist.com/forums/996-foru...w-by-test.html

Here is a link to a thread I just did 3 days ago with a video from a fellow Cayman owner that shows how to do the test on a Cayman, and also shows he had excessive blow-by ( 170 LPM !! ). He had some bore-score on cyl #6 ...https://rennlist.com/forums/996-foru...-in-point.html

There will always be oiliness in the intake system due to oil vapors, but should NOT be enough to pool oil or to smoke on start-up ( or on the Track in corners).

The OEM AOS doesn't do a good job of separating the oil droplets from the vapor, the UAOS is 4X more efficient at doing that, But if there is too much blow-by ( excess of 100 LPM ), then there is an issue in the engine...

Beachproducer

Thanks for this, very helpful