8 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHAOS?
Leading reported evidence
Check asap
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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.
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.
Leading evidence: 'Check asap' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check asap' (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.
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.
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.
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.
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
Have you checked your oil level with the dipstick?
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.
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
Are 996's checked with engine cold and stopped, or warm and running?
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.
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.
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.
8 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.
1 acknowledgements have no verified action link; they do not establish a repair result.
My 2002 C4S put out an enormous cloud of smoke a couple of weeks ago when started after having been left in the garage for a week.
Since then nothing.
Today, having driven the car daily, another cloud of smoke at morning startup. Clears quickly, but quite a lot of smoke.
Went out at lunch, and smoke again in the garage. Left car sitting for 2 hours, small amount of smoke, clears quickly, and no stall when I remove the oil cap, but revs do stumble.
Thoughts?
Was serviced not long ago - will check ASAP. Are 996's checked with engine cold and stopped, or warm and running?
Wouldn't oil smoke be blue and heavy?
My car used to smoke after lapping at the track. A new AOS solved the problem. If you idle the car for a few minutes before you turn it off you will avoid the cloud of smoke when starting. Still, look into replacing AOS.
Are these smoking events coming after short trips during which the engine doesn't get up to full operating temperature?
Are you allowing the engine to idle a moment or two before shutting it off?
Is the engine oil level ok -- not too high for one thing -- and if the engine filled with some approved oil and the oil doesn't have too many miles or too much time on it, and if the smoking events are coming after short trips with no idle time prior to engine off with the fact there is no CEL or other signs of engine distress like a erratic/hunting idle, then the smoking may be explained away as being normal given how the engine is being used.
The engine reacting to the removal of the cap is to be expected since the removal of the cap causes a large intake air leak which the DME will attempt and succeed to some extent in adapting to.
That you can unscrew and remove the oil cap is not 100% proof the AOS is ok.
There is I believe either 2 AOS failure modes, or one failure mode with at least two different phases.
In one phase (an early phase?) the cap can be removed without any difficultly while in second (later/more advanced phase?) the cap is hard to impossible to remove against the extreme low pressure the crankcase experiences arising from a malfunctioning AOS.
Since an AOS failure puts the engine at some risk of additional/collateral damage I would urge you to have the car checked out by a qualified tech.
Sincerely,
Macster.
1st event came after the car was left for 1 week plus. 2nd event came after spiritd drive, engine shut off with no extended idle, and cold start after 12+ hours. 3rd event was after 4hr parking with very mild drive to work (30mins). Oil is 1500kms old after an OPC service. Will check oil and coolant levels tmw morning.
With the motor running, take off the oil filler cap, put your hand over it to seal it. You should feel just the slightest vacuum. If you feel any significant vacuum, the AOS is bad.
