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YOUR RESEARCHChatter Noise From Engine - Alternator or PS or ??
Reported or suspected cause
alternator
Reported cause
No successful repair reported for this finding.
1
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0
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0
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Chatter Noise From Engine - Alternator or PS or ??
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Leading evidence: 'alternator' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'alternator' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check bolts' (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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Suggestion
Check the bolts on the power steering pump pulley.
Chatter Noise From Engine - Alternator or PS or ??
Recommend hf stethoscope
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Suggestion · Original poster
I would highly recommend the HF stethoscope to help you narrow down the location.
Chatter Noise From Engine - Alternator or PS or ??
Replace then the ps pump
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Suggestion
If u want to just throw parts at it the alt is much easier to replace then the ps pump.
Chatter Noise From Engine - Alternator or PS or ??
Replace when it goes
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Suggestion · Original poster
This video was just after start up and you can hear how the noise changes when it goes to idle.
Chatter Noise From Engine - Alternator or PS or ??
Coverage and how to read this overview
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.
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Generation: 20261027T184158Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
My C4S has developed a weird chatter noise that can be heard from within the cabin and when listening at the engine bay. It is a chatter/rattle sort of noise that comes and goes randomly but sounds rotational and somewhat corresponds to the engine speed. I changed the two idler pulleys, tensioner, and alternator pulley, hoping to solve the issue, but there was no change in the noise. My local indie shop thinks it's the power steering pump, but to my ear, it sounds more like the alternator. Has anyone heard something like this before? Any suggestions?
This video was just after start up and you can hear how the noise changes when it goes to idle.
Video
With the belt off u should be able to feel a bad bearing in one or the other when u spin them. This will tell u which one is bad. If u want to just throw parts at it the alt is much easier to replace then the ps pump.
Ahh, good suggestion. Water pump was done before I bought the car at about 5 years and 5000 miles ago, but by the same shop that apparently forgot to install all the bolts back in the transmission when they did other work. I'll listen under the car as well.
I bought one of these stethoscopes today. It still sounds like the alternator. I can hear the noise in other components, but it is clearly loudest in the alternator. I've ordered an alternator to see if that fixes the issue.
Do you hear the noise that strongly from anywhere else? Front of engine or underneath around the bellhousing area?
I have a very similar sound on my 99 but I can hear it more strongly underneath the car at the bellhousing area.
I initially thought it was coming from the transmission area because of the way I heard it so well in the cabin and even through the handbrake vibrations. In my case, though, it was the alternator. I changed it today, and the sound is gone. I would highly recommend the HF stethoscope to help you narrow down the location. The indie mechanic was really leaning toward it being the flywheel until they removed the belt, and the sound stopped. Good luck!
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