Robin 993DX

Does anyone know what this little t-shaped breather is call? and part number?

Thanks

Dharn55

That is a breather line that runs from the AOS to the 4-6 cylinder head. I think the part number for the connector is 996.107.047.51, crankcase vent elbow, but don't hold me to this.

rb101

Looks like your AOS is going bad and blowing oil out the vent. You can pop the elbow apart and clean it.

Rick
99 996C4
87 944S

Robin 993DX

Rick,

AOS was replaced. So I guess I will just clean it out then. Thanks

rb101

If I remember correctly, it's just a spring and a check ball inside.

Rick
99 996C4
87 944S

Eharrison

Hey Robin becareful of those vacuum lines! I broke one last week on the AOS because I pulled the rubber bushing on the plenum too hard!

supafin

Bumping old thread.
How should this vent valve work? I removed mine to clean it and it seems it has spring and check ball inside but no matter how hard I blow or suck, it doesn't open.
It looks like it should open if there is excessive pressure inside crankcase.
In what kind of case that would happen?

I'm trying to find cause for unusual noise with part throttle and also around 2000rpm.
I want to verify if this part it function OK or not.

DBJoe996

It is a crankcase bleeder connector for the AOS system. You are correct, it should open if there is excessive crankcase pressure, like a pop off valve. For $25 I would just replace it. http://www.einmaligparts.com/Crankca...10_c_7807.html
Excessive crankcase pressure - bad/worn piston rings, leaking valve stems and seals, all kinds of bad things
Normally the crankcase is under vacuum as well as the intake manifold. i guess the engine designers felt that under rare circumstances where excessive crankcase pressure could occur, it is better to have the pressure relieved than to blow out seals all over the place. I have no idea when that might occur under normal driving.

RennPart

.. We had a similar leak on our spec Boxster (uses the same part). Turns out we were running the car with too much oil on the track hence the leak. On the SPB we run 1/3 oil on the dipstick when cold I do not recommend this for a tracked 996 as you're moving more oil since you are at least 3.4L and the SPB is 2.5L.

..We also replaced our AOS as preventive maintenance.

https://rennpart.com/carrera/carrera...tenance-parts/