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AOS vent line tubing - OK or not?

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3 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis

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YOUR RESEARCHAOS vent line tubing - OK or not?

Leading reported evidence

Replace (note

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

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Discussions that performed work without a confirmed outcome: 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.

Performed · outcome unconfirmed · Original poster
(Note that my AOS was replaced about 15k miles and 10 years ago).
Original post Read captured discussion
AOS vent line tubing - OK or not?

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Leading evidence: 'Replace (note' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace (note' (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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Replace tube

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

Discussions that performed work without a confirmed outcome: 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.

Performed · outcome unconfirmed
When I did my starter a few years ago I found the same kind of thing and replaced the tube.
Original post Read captured discussion
AOS vent line tubing - OK or not?

Replace i'm trying

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Unsuccessful attempts: 1
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Suggestion · Original poster
If it should be replaced, I'm trying to judge how difficult it would be to do so.
Original post Read captured discussion
AOS vent line tubing - OK or not?

Frequently discussed actions (3)

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Replace (note

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

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Discussions that performed work without a confirmed outcome: 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.

Performed · outcome unconfirmed · Original poster
(Note that my AOS was replaced about 15k miles and 10 years ago).
Original post Read captured discussion
AOS vent line tubing - OK or not?

Replace i'm trying

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

Discussions that contain suggestions: 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.

Suggestion · Original poster
If it should be replaced, I'm trying to judge how difficult it would be to do so.
Original post Read captured discussion
AOS vent line tubing - OK or not?

Replace tube

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

Discussions that performed work without a confirmed outcome: 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.

Performed · outcome unconfirmed
When I did my starter a few years ago I found the same kind of thing and replaced the tube.
Original post Read captured discussion
AOS vent line tubing - OK or not?

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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.

3 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: 20261027T140027Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

I'm in the process of changing out the starter on my 2003 996. I noticed this corrugated tube the runs from the left front portion of the engine (at the AOS I think) to the right rear portion of the engine. I think (please confirm if so or if I'm wrong) this is the AOS vent tube. As the photos show, there is an oily section of the tube in the middle portion and a smaller patch on the left portion of the tube. Should I be worried that this tube has some microcracks and should be replaced? If it should be replaced, I'm trying to judge how difficult it would be to do so. The connection at the AOS seems very hard to get to... maybe I can get to it from below the car but not sure. Any guidance or feedback would be appreciated. Thanks. (Note that my AOS was replaced about 15k miles and 10 years ago). Red encircled area shows oily tube surface. Center portion of tube. Red encircled area shows oily tube surface. Left portion of tube. Right portion of tube looks clean.

POST 2Original post

When I did my starter a few years ago I found the same kind of thing and replaced the tube. After removing the tube it was clear it was weak/cracked. I don�t recall it being very difficult to do the replacement.

POST 3Original post

You could take it out and pressure test it for leaks , but as old and brittle as it probably is itt will break/fall apart while removing, so just buy a new one and replace it ...

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