37 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHMy AOS adventure...
Leading reported evidence
Replace air oil separator
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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0
Unsuccessful attempts
1
Discussions
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Discussions that performed work without a confirmed outcome
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1
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Suggestion
Have any of you who track your cars considered replacing the AOS with the motorsports version?
Leading evidence: 'Replace air oil separator' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'material fatigue' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check bellows' (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.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Discussions that suspect a cause
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Suspected cause
I cut a bad one apart with a fine pitch hacksaw blade fitted in a hacksaw and found the canvas/rubber diaphram inside the large flat/round housing had a tear/crack in it from I suspect material fatigue.
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Suggestion
It is my opinion that if the AOS is leaking it is close enough to failing to qualify bring replaced without waiting for the symptoms to get worse or more numerous.
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Suggestion · Original poster
You really only need a couple screw drivers (common and Philips) a socket set (shallow and deep well) with 7mm - 15mm, 3/8 extensions (two 6 in), 1/4 extensions (one 3-4 inch) and a pair of pliers or adjustable pliers for the AOS boot.
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material fatigue
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
I cut a bad one apart with a fine pitch hacksaw blade fitted in a hacksaw and found the canvas/rubber diaphram inside the large flat/round housing had a tear/crack in it from I suspect material fatigue.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
37 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T172408Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
So I decided to jump into the AOS replacement today.. Whats the trick for the last intake manifold bolt again? It seems that the old AOS is directly on top of the bolt.... limiting access.. everything else has been easy though... I found something pretty interesting underneath the manifold. I will post pics later.
I don't know if you've seen this before but I've been studying this PDF in anticipation of what I have to do for mine:
http://www.renntech.org/forums/index...placement-aos/
Fernando, that's an excellent How-to. I could've used that when
I
took this job on myself last winter. The only thing I would add to the discussion is that it's so easy to lower the engine down a few inches that it should be done to gain that much more room up top.
Here's
my
documented experience with the job:
https://rennlist.com/forums/996-foru...separator.html
you should be able to move that AOS out of the way by now.... just take the 2 bolts that holds the AOS off and move the aos... this should make enough room for the intake bolts.
Or are maybe its the vac tank your are talking about... the trick is, the more you clear, the easiser to take out.
here is where the bolts are located....
I have no idea. I saw the corroded wire while I was fulling the intake manifold off and its the main wire coming from alternator and starter... fun.fun
Don't worry rags are in the holes.. I just finished replacing the AOS and oil filler tube. That AOS job was sooo easy compared to my fuel pump. Oil filler tube was a matter of removing two bolts and thats it.
Just how long should one plan on for doing a job like this ? A day...a weekend ? Mine looks to be pooched too and if the job is a 5 out 10...then I might give it a go if it could be done in a day (2 tops).
what symptoms did you have that prompted to R&R the AOS?
Only way to tell really is to tear the AOS apart, if the diaphragm inside crumbles in you hand, its done.
Well, I've had some oil consumption and traces of oil behind the throttle body. Seepage around the intake manifolds (at the clamps) Also, I pulled the oil cap off while running and had excessive vacuum at the opening of the fill tube. My idle was also erratic sometimes and a experience a slight howling from the engine during certain RPM's after start up (sounded like an air leak or air blowing by a valve) I also needed a new Oil filler tube so I figured it was time...
Plus its a good thing I pulled of the intake manifold otherwise I would not of found that burn wire from the alternator.
For the record.. I simply removed the air intake, throttle body, air pump, alternator and the driver's side intake manifold to access the AOS. I did not lower the engine or remove the coolant reservoir. The hardest part was attaching the rubber boot to the block from the AOS with the clamp.
Wow you're an inspiration for me to get this done!
Did you need to order any other parts for this job aside from the AOS? I know your alternator has issues now but for the core job was anything else needed? I wanted to make sure I had all parts on hand before giving this a try.
I only thing I ordered was the AOS and an oil filler tube w/ o-ring. I know most people replace the intake manifold gaskets but I opted out. Mine were still in good shape anyway. Prepare to break little plastic tabs on various connectors and clamps. Some were fairly brittle. It doesn't really matter though, its a car not an airplane. Feel free to message me with any questions once you drive into the project. I found the entire replacement very easy and accessible after moving a few components out of the way. Good Luck.
No bench test I can think of. I cut a bad one apart with a fine pitch hacksaw blade fitted in a hacksaw and found the canvas/rubber diaphram inside the large flat/round housing had a tear/crack in it from I suspect material fatigue.
Sincerely,
Macster.
Well, I got the new harness today. It should be a huge pain in the a** since the connectors are too large to fit through the right side intake manifold....
Your going to need more tools than that. You really only need a couple screw drivers (common and Philips) a socket set (shallow and deep well) with 7mm - 15mm, 3/8 extensions (two 6 in), 1/4 extensions (one 3-4 inch) and a pair of pliers or adjustable pliers for the AOS boot.
Oh well....about 2 miles before getting home I was stopped at a red light. The idle started to fluctuate unusually weird and as I left in the rear view mirror...white smoke. I immediately pulled over and turned off the engine upon further inspection I didnt see any oil or coolant dripping. So I started the car up again and white smoke, oil pressure held, temperature remained stable...so i coasted home.
I did the test where I tried to pull of the oil cap (on tight and air sucking when removed) and the car almost died...soooo AOS replacement this weekend. Im just thankful for Rennlist and these DIY tutorials..
Just an Update:
I reviewed all the DIY post on Rennlist and Renntech in which I developed my own plan of attack. The DIY on Renntech has you removing the air pump, coolant tank and alternator in order to get to the AOS. The DIY on Rennlist has you removing the manifold without removing any of those components. My approach was a hypbrid of the two in which I only removed the alternator. I removed the alternator in order to get more access to the manifold bolts by sliding my hands underneath the manifold. I was able to reach the far back bolt without any issues or loss of patience. This was an ideal time to also check the belt for any cracks as the serpentine belt needs to be removed.
The project from start to finish took approximately 5 hours and some of the key points to point out are:
-Patience…have plenty of it
-Make sure the AOS is seated correctly and grease the grommet prior to installing.
-Do not over tighten any bolts as they will strip
-Make sure the couplers on the intake manifold are aligned correctly (I had them misaligned which caused severe backfire when I restarted)
-Extensions to get to the AOS bolts
-Use a regular hose clamp when reinstalling the bellows
-The AOS i ordered from Porsche comes with the bellow ($135 with PCA discount)
-And finally patience….
Links for reference:
Renntech:
http://www.renntech.org/forums/index...placement-aos/
Rennlist:
https://rennlist.com/forums/996-foru...separator.html
Have any of you who track your cars considered replacing the AOS with the motorsports version? (Here at Suncoast for $730:
http://www.suncoastparts.com/product...ry_Code=996Oil
I had my car in recently for clutch, DMF, IMSR and found the AOS to be leaking a bit. My indy recommended waiting for it to fail and then upgrading to the motorsports version. I do DEs and am on the slippery slope...., but I'm not sure this is a worthwhile upgrade, especially given its expense. What do you all think?
In any case this will be a DIY, so thanks Alex for the procedural notes.
David
Mo-sport AOS doesn't work on 996 (at least early MY M96-01 engines), not sure why Suncoast lists it as fitting a Carrera... at least I've never heard of someone being able to make it fit without a lot of hacking.
It is my opinion that if the AOS is leaking it is close enough to failing to qualify bring replaced without waiting for the symptoms to get worse or more numerous.
It is bad enough when an AOS fails while one is just tooling around the neighbor, but on the road, and especially on the track... oh boy.
I'd not wait but the AOS replaced now.
Sincerely,
Macster.
Logray: It doesn't surprise me that it doesn't fit. Thanks for the info.
Macster: Yeah, my gut told me to have it done while we were in there...but I didn't. Now I'll have to tackle it myself. At least I'll learn my way around the engine a bit better!
David
The bellows come attached with clip to the bottom of the AOS. I SAW ON YOUTUBE IT IS BEST TO SECURE THE aos BRACKET TO THE ENGINE BEFORE ATTEMPTING TO PUSH THE BELLOWS ONTO THE BOTTOM PIPE. tHE TOP AND BOTTOM SNAP CLIPS ARE DIFFERANT SIZES I BELIEVE. sorry for caps. I had to order the bellows as mine was leaking after a (so called indi) replaced my AOS when doing a job on my gearbox. The bellows are dirt cheap but they advise a quick release clip with a blue plastic pull off release tab be bought at the same time. That's dirt cheap as well. Pelican have the quick release clips with blue plastic tab. You can check your bellows from under the car. Then pull the tab off and Bingo. That should be the last part of the installment. Pelican has a DIY where early and later 996 yrs are explained.
http://www.pelicanparts.com/techarti..._Separator.htm
I replaced my AOS last weekend. It was a bigger job than anticipated. I did not drop the engine or take out the coolant tank.
QUOTE=Hurdigurdiman;14018379]Sorry for bringing up a 6 year old thread but I found it real helpful.[/QUOTE]
This is a source reference. Confirm exact model applicability in the original material.
