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Discussion summary
YOUR RESEARCHSmoke from drivers side tailpipe when started cold?
Leading reported evidence
Replace i don't think the aos
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Smoke from drivers side tailpipe when started cold?
Frequently discussed work
Check oil
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Suggestion
Also, an internally cracked AOS can release a great deal of coolant into the engine, usually found by checking the oil for water or a rise in oil level.
Smoke from drivers side tailpipe when started cold?
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Leading evidence: 'Replace i don't think the aos' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is '#1' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check oil' (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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Suspected cause
Still, I agree with others that the AOS is prime suspect #1.
Smoke from drivers side tailpipe when started cold?
Check oil
Suggestion or failed attempt
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Suggestion
Also, an internally cracked AOS can release a great deal of coolant into the engine, usually found by checking the oil for water or a rise in oil level.
Smoke from drivers side tailpipe when started cold?
Replace air oil separator
Suggestion or failed attempt
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Smoke from drivers side tailpipe when started cold?
Replace aos three weeks ago
Suggestion or failed attempt
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Suggestion
My Indy charged me $966 to replace my AOS three weeks ago.
Smoke from drivers side tailpipe when started cold?
Frequently discussed actions (6)
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Check oil
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Suggestion
Also, an internally cracked AOS can release a great deal of coolant into the engine, usually found by checking the oil for water or a rise in oil level.
Smoke from drivers side tailpipe when started cold?
Run engine
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Suggestion
You need to avoid running the engine to avoid the risk the AOS dumping so much oil into the intake that one or more cylinders suffer from hydraulic lock up.
Smoke from drivers side tailpipe when started cold?
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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.
16 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Hi Everyone.
My '99 996 automatic/tiptronic, puts out quite a bit of smoke out of the drivers side tailpipe when it is started cold. The smoke stops once it has warmed up. The car has 34,000 miles and has been well cared for.
I'm sure others have seen this.
What is the typical cause? Is this something that has to be addressed right away or can I leave it alone.
The oil and coolant levels don't seem to be dropping as far as I can tell.
Let me know what you think.
Thanks for the quick replies.
I don't think the AOS has been replaced. We are at least the 3rd owner (another family member was the previous owner).
It's 17 years old and has 34,000 miles.
I'll check to see if the air vacuum exists as demonstrates in the video.
How expensive is it to replace the AOS?
depends if you DIY, indy or dealer? for a TIP, engine may need to be dropped. good time to address other "while you are in there" items like IMSB, RMS, etc.
http://www.renntech.org/forums/topic...o-replace-aos/
My Indy charged me $966 to replace my AOS three weeks ago. Mine just completely let go with no warnings. My car is a 3.6 though, and a manual so no engine drop.
Just finished 3 hours of highway driving so there hasn't been any smoke since the engine got hot.
I left the engine running and twisted off the oil cap (as demonstrated in the video). There was a suction sound as I took the cap off and the engine idled/sounded differently, but still no smoke. I'm not sure if this is normal (the suction when the oil cap is removed).
I'll try taking off the oil cap again when I start it cold tomorrow.
The oil cap being hard to impossible to remove when the AOS is bad is not 100% reliable. The AOS may not have failed enough or there can be a AOS failure mode that doesn't result in generating the huge pressure difference.
That there was some suction and the engine reacted is normal as removing this cap creates a big air leak.
Still, I agree with others that the AOS is prime suspect #1. While the miles are *not* huge -- I get around 80K to 100K miles from an AOS with my 2002 (300K mile) Boxster -- your car is old enough the AOS can have just failed due to age.
You need to avoid running the engine to avoid the risk the AOS dumping so much oil into the intake that one or more cylinders suffer from hydraulic lock up.
Get the car to a qualified shop for proper diagnosis and repair.
AOS - replace and drive on.
Bore scoring - your engine is toast.
If it is just smoking from the tailpipe, like bluish smoke..AOS (Air Oil Separator). Also, an internally cracked AOS can release a great deal of coolant into the engine, usually found by checking the oil for water or a rise in oil level. Either way, bad. New AOS
