kkswow12

hi, I am wondering if there is a valve needs replacing or cleaning, I think it is the PCV valve if these cars even have that anymore, I remember years ago they used to vent into the valve covers in my old v-8 buick from the 70's...I see a small, maybe 3/4" hose going into the intake behind the MAF(?) at the beginning of the intake manifold and oil is getting out and on the intake by the large rubber gasket, I a thinking macster will have some insight here...? thanks in advance, as always, kevin

Bijan

In our cars it is now the Air Oil Separator (AOS)
This link may help:
https://rennlist.com/forums/997-foru...-997-1-c2.html

kkswow12

could I be looking at doing the AOS replacement...is this how it starts?

utkinpol

consider installing motorsports AOS - they last longer. if you see oil in the intake consider doing this job ASAP. it is a known problem.

to replace AOS it is usually simpler to do it with having gearbox dropped so if your clutch is due to be replaced you can consider going this way as shops charge 7-8 hours labor on AOS install with gearbox not taken off, otherwise it is a 1.5-2hr job. check with your mechanics on details as rates may differ.

Macster

Well, I'm not an expert or professional technican but my take is a failing AOS usually makes itself known by affecting the engine, how it runs.

The hose you describe I believe runs from the AOS to the connector at the intake manifold and the hose does carry some oil, that is oil in the form of vapor. Some of this oil in the vapor will end up on the hose walls and further into the intake.

If the hose has a crack or split or there's something wrong with the connection it would not be out of the ordinary to have some oil in that vicinity.

But this doesn't mean the AOS is bad.

You or someone is going to have to get his hands dirty and make a diagnosis. If just the hose is bad then doing an AOS is an unnecessary expense.

But of course if the AOS is bad then it needs doing and the little hose too for good measure.

utkinpol

nope, not really. amazingly in 997 cars it may/does not show up much. on 996 cars it would be obvious as car would be making more and more smoke especially running at WOT, on 997 cars it will add up some smoke at startup but when car is running it may not smoke up more and run almost ok until it will finally suffer a hydraulic shock from too much oil in the cylinder and that is kaput.

all I can tell - disconnect airbox and put your finger inside of the throttle body when you open it fully. my throttle body is dry and grey, it should not have any oily residue and dark wettish soot spots. it is easy to see if you get oil into intake, if it makes it there - it has to be fixed.

kkswow12

well so far I am fortunate in that the oil is on the outside of the intake... not the other way round, and she runs fine, no smoke at start-up, or anytime, as far as I can tell...so it is basically cosmetic. there may be a fault in the hose...my next step, i'll see...can I just replace that hose or , well I will look into it tomorrow, and thanks all for your input...