Strange fluttering / whistling noise from ’02 Civic EP3 (K20A3)

[AB]

I bought this car about 8 months ago and it’s always made this odd fluttery whistling sound. I’ve had three different mechanics for ride-alongs and they’ve all said not a sound they’d worry about. One suggested it might be normal intake and/or valvetrain noise. I can accept that, but it’s starting to annoy me and I’d like to get rid of it.

Recording of noise

Characteristics:

• Only occurs under load.
• While parked or coasting, if it’s in neutral (clutch in or out) or in gear (clutch in), I can only hear it for the brief split second while blipping the throttle.
• Frequency follows RPM. At higher RPMs, it sounds more like ringing.
• It seems to be originating from the front-right, but it’s impossible to narrow down further because it only happens under load. I can’t hear it while standing in front of the car with the hood opening and blipping the throttle (normal engine noise drowns it out).

Car is totally stock with 184km. No CEL or warning lights.

Maintenance I’ve done to date:

• changed the oil and filter a couple of times (5w20 H/M full syn)
• replaced air filter
• replaced PCV valve and breather hose
• replaced spark plugs (old ones looked good)
• replaced idler and tensioner pulleys

[li]replaced donut gasket (between header and downpipe/cat)

I have no idea what else to look for or how I could narrow it down. Help?

Topic

[Joe Maggio]

Same issue here. Did you ever resolve this?

[Author]

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