16 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH996 Intermittent Noise on Startup
Reported or suspected cause
tensioner
Suggestion or failed attempt
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
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 suspect a cause
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
Likely a tensioner that's needing changing, but there are a few other things running off that belt.
Leading evidence: 'tensioner' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'tensioner' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Disconnect air filter box attached' (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
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Suggestion
If it turns out to be the source, remove from the car, disconnect the air filter box attached to it and blow it all out with compressed air.
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
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Suggestion
That is the typical Bosch "dry starter bushing noise".....Just replace the starter and you will be good..
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
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Suggestion
I believe it is the starter solenoid being slow to disengage and will be replacing the starter soon.
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
Sounds like the serpentine belt running across something that is reluctant to turn.
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
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: 20261026T122219Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hey everyone!
I just purchased a new (to me) 1999 Porsche 911. It has ~95,000 miles, and is nearly perfect. However, occasionally on startup, it will make a strange whirring-type noise for a second or so after ignition. The car runs and drives perfectly well aside from this noise on startup. I have a youtube short with the noise posted below.
Has anyone else heard this noise from their 996 before? My hunch is that I'll need a new starter motor soon...
The car seems to make the noise more often on hot starts, but it definitely doesn't do it every time. I've only had the car for 2 days so not enough time to figure out exactly what circumstances cause it.
You Tube
Thanks all in advance!
Yup, that's unusual. Have someone stand in the back with the hatch open to see where the sound is coming from. Sounds like the serpentine belt running across something that is reluctant to turn.
Does sound like a belt slipping sound. Could be a worn serpentine belt?
Likely a tensioner that's needing changing, but there are a few other things running off that belt. Easy to pull the airbox out and take belt off to check and also the pulleys of power steering, ac, alternator and waterpump.
996's can have a few noises on startup, from failing tensioner bearings, starter motors and even exhaust shield rattles.
Mine does the same thing, almost always on hot start not cold. I believe it is the starter solenoid being slow to disengage and will be replacing the starter soon.
That is the typical Bosch "dry starter bushing noise".....Just replace the starter and you will be good..
Some adventurous people try to disassemble and grease the bushing, but that is "easier said than done ".......
I've heard this noise before on a 996...I think it is the secondary air pump (part of the emissions system) which is located just behind the coolant expansion tank. Cleaning this part as well as the associated hoses could do the trick. The fact that it only occasionally makes a noise is a clue that it is the air pump.
I'm not convinced that is the secondary air pump squealing, but there is a sure way to find out. Disconnect this connector (circled here) and start up when cold. If it turns out to be the source, remove from the car, disconnect the air filter box attached to it and blow it all out with compressed air.
I could be wrong but I've fixed this issue before on a 996 and the noise the offending car made (occasional noise for a couple of seconds after starting) sounded exactly like the sound in the OP's video.
I will add another, "it's the starter", to the list. I think the secondary air pump does not run immediately after start-up so that is not likely the source of this noise.
FIFY. But that is a good point.
The problem car I was referring to only made the noise occasionally during cold starts - not hot starts. The noise the OP is experiencing, however, certainly sounds to me like a noisy secondary air pump.
Yeah, I was wondering if that noise was a bushing or a bearing. I have a cordless portable vacuum where the bearing is intact, but the carrier has failed (came apart and is loose and spinning) on the bush head and makes a similar noise now. Interestingly, this is a roller bearing and I can only find a replacement online for about $30 shipped, even though it�s the size of a dime, and the whole vacuum was only $200.
