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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHMotorsports Cup AOS leaking oil
Leading reported evidence
Replace air oil separator
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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0
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1
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Read evidence and context
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Performed · outcome unconfirmed · Original poster
Looks like one of the previous 2 owners replaced the AOS with the very pricey Motorsports Cup AOS
Leading evidence: 'Replace air oil separator' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check with a mechanic' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed
The late "Karlooz" ran his 99' 3.4 to a proper catch can apparently without issue.
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Suggestion
I bought the kit from Suncoast also without first checking with a mechanic.
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Suggestion
That combined with the high vacuum the new 3.8 pulls means I'd be replacing the stock AOS pretty regularly.
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Suggestion
I'll just replace the stupid part if and when I drop the motor.
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Generation: 20261027T005001Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I just picked up a Seal Gray 2002 911 C2. Excellent condition, body is near perfect for a 10yo car, and it's nicely optioned out. It's my first Porsche, and needless to say it's an amazing car!
Now the bad...there was some oil residue on the driver side 1-3 cylinder bank head, and I traced it back to the AOS above. Looks like one of the previous 2 owners replaced the AOS with the very pricey Motorsports Cup AOS
http://www.suncoastparts.com/product...ry_Code=996Oil
, and the elbow on the top most part of the AOS is dripping oil. It's not leaking bad enough for oil to pool while the car is parked, but everything below it is pretty much covered in an even film of oil/dirt.
There are no traces of oil in the intake tract behind the throttle body, car's not smoking, no codes, and I can pull the oil filler cap off and the car still runs (albeit idling about 100rpm higher). Could this be indicative of another problem? Did the AOS diaphragm go bad and need replacement, or is this amount of oil accumulation normal? Does potentially the clamp around that elbow just need to be tightened to lock in the vapors properly to be ingested into the intake?
I'll probably have to go through the trouble of pulling this thing out anyways to address the leak, but I was hoping someone has some experience with the Motorsports Cup AOS and could comment on what's normal. Thanks.
I just had the Motorsports AOS installed in my 03 Seal Gray C2 last week at Orbit. They had to fabricate all of the hoses and fittings as the hose that comes with the Suncoast only works worth Boxsters /Caymans. If the guy that installed yours had to do the same thing there could be several spots where it could leak. Full disclosure: I am not a DIY'er, just passing along what Orbit told me. GL
There were created for the 996 Koni cars so that doesn't make any sense. Still, there not a OEM part so some creative fitting may be required.
PS: The use of the word "CUP" by Suncoast in the part description is a misnomer. Cups don't have AOS's....
For the OP you'll probably need to drop the motor down some to access the part and see if your leaking elbow can be replaced or repaired....
Ya, from what I can see from below the car, the hose attached to that elbow is held on with only a zip tie, so a worm clamp would hopefully resolve the leak. But is that elbow part of the oil return line, or does that feed back into the intake?
They're very expensive expecially considering the OEM AOS is only $110.(+/-). I don't think anyone races a 996 more than me in recent years and I don't have one on my car. I'll just replace the stupid part if and when I drop the motor. I had one start smoking on me several years ago but it was a original part with high mileage. Never since....
I've read anything from it's not possible to it might require literally cutting into the AOS and re-plumbing it to make it fit.
For me whatever $800 or so is $ it costs doesn't sound like it's worth it, just keep on top of replacements.
Sorry I forgot to mention, it might be more possible on a 2002-2004 model year lees of a headache but still some creativity.
1998-2001 models are totally different.
I bought the kit from Suncoast also without first checking with a mechanic. The AOS itself may have been originally designed for Koni cars but the kit Suncoast includes a hose and fittings that are of no use in a 996. The work involved is extensive. Flat 6 rebuilt my motor and had the kit I bought from Suncoast in hand and declined to install it after seeing what was involved in piping it. That's not intended as a shot at Flat 6. Engines are their bread and butter and spending a lot of hours coming up with a solution to install a part only one in thirty of their future customers will ever ask for doesn't make sense.
I live and track at basically sea level. That combined with the high vacuum the new 3.8 pulls means I'd be replacing the stock AOS pretty regularly. Possessing little or no mechanical aptitude, I bit the bullet for the installation. I might not have if I hadn't already purchased the MS one. I'll get some installation info from my guy and send it to you.
Is there a reason people don't just replace the AOS on these cars with a proper catch can setup? Maybe I'm missing something about how the AOS functions?
Some have but the thought was that the system operates under vacuum to help eliminate foaming in the sump. Draining it to a catch can would eliminate the vacuum. The late "Karlooz" ran his 99' 3.4 to a proper catch can apparently without issue. I eliminated it and reinstalled a new AOS when I bought the car a few months back....
Not an attempt to highjack this thread but...
I have a new one of these so called Motorsport AOS that came with my Koni car when I bought it. If anyones interested in it make me an offer.
^^^
Its a VF supercharger setup with a catch can... I can't even remember the amount of mods Ive done to it. Catch can def works though... Its a custom can.
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