13 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHSquealing Noise on Start up
Reported or suspected cause
secondary air pump
Reported cause
No successful repair reported for this finding.
1
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 report identifying a cause
1
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.
Leading evidence: 'secondary air pump' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'secondary air pump' (1 discussions; 1 report identifying it and 1 suggest it). The most frequently discussed action is 'Check coolant leaks' (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.
Suggestion
Check the WP pulley, if it has any play at all, its bad, also check for coolant leaks from the pump.
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
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Suggestion
I've heard you can disconnect the air hoses from the pump and blow things 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
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Suggestion
I don't recall the noise being present when I bought the car, so I guess I should replace the pump.
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
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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
You can disassemble the secondary air pump and clean it out and it will run quiet after that.
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.
13 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: 20261026T135432Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
When I start my car up after its sitting over night (02' C4 Cab), I often hear a high pitched squeal coming from the engine and it goes away after about a minute or so. I have recorded the sound on my phone but can't find a way to upload it to the forum so I am open to any suggestions as to what it might be before I bring it over to the indy and hand him my wallet. I realize that's not much to go on and i apologize up front. Thanks!
I would guess based on your description it is probably the secondary air pump, but it could be an accessory pulley. Depending on how it sounds, it could be perfectly normal (like a vacuum cleaner sound). But if it is more like fingers across a chalk board then it's either the emissions air pump going bad, or a pulley bearing that is on it's way out.
Without the sound recording it's more difficult to tell which it is for certain.
Since you can reproduce the problem, open the engine bay, start the engine, then walk to the back of the car and you should be able to easily hear approximately where it is coming from, then report back here. Don't get anything caught in the belt as it is spinning around (hair, necklace, etc.)
Take the accesory belt off the motor and start the car (don't run it very long as you have no alternator or water pump at this time.) If the noise is gone, its one of the accesories, the belt or the pulleys. Water pumps will make this sound when they get bad. Check the WP pulley, if it has any play at all, its bad, also check for coolant leaks from the pump.
I have a high pitched whine on my 996's air pump as well. Is the high pitched whine unusual, or a common ocurrance? I don't recall the noise being present when I bought the car, so I guess I should replace the pump.
Rpolin - what did you do with yours?
Rob
I confirmed with my indy that it was the secondary air pump and his advice was don't worry about it. If i recall, i believe he said that it has something to do with warming up the catalytic converters when the car is cold and it really only effects the emmission so its nothing to lose sleep over. Of course i can get it freplaced if i want but nothing worth rushing to do by any means so i'm leaving it alone for now
I've got the same thing (high pitched squeal on start) that was also diagnosed by my mechanic the same way, he called it a "dustbuster" that's designed to heat up the catalysts.
