View Full Version : Strange whining noise above 4k rpm N15 SSS

25-05-2017, 07:24 PM
Hey guys,

I'm having an issue with my N15 SSS where I seem to be getting an irritating whine/buzz noise above 4k rpm.

I have only noticed it since the car was recently stolen. At first I thought it was alternator noise coming through the stereo (which helps explain what it sounds like) however I completely disconnected the stereo from the harness to isolate it and determined it's not the source of the irritating noise.

The noise is directly relative to rpm and seems to worsen as rpms rise above that 4k-ish mark. It occurs under all conditions, stationary, full load and everywhere in between.

At this stage, I haven't been able to locate which area the noise is coming from as it's obviously very difficult to hear anything at those revs under the bonnet and I'm none the wiser poking my head around different areas of the interior.

I was hoping one of the resident gurus might have come across this before and could perhaps point me in the right direction. I'll try to get a video tomorrow and see if the noise is apparent in it.


26-05-2017, 11:27 AM
Ok so I got a little video on the way to work this morning, it may be difficult to hear but I'm sure you can hear it.
I realised it occurs under 4k as well, but seems to be dependent on load perhaps?
It really does sound like alternator noise through a stereo!
It's annoying the hell out of me.

Leroy Peterson
26-05-2017, 05:02 PM
Silly question: do you have a pod filter? Or modified airbox?

26-05-2017, 05:07 PM
Radio buzz ? alternator whine through the radio.

26-05-2017, 08:58 PM
Silly question: do you have a pod filter? Or modified airbox?

Hey mate,
Not silly at all, the car is completely stock apart from a pioneer head unit and some Kevlar response speakers, which I've fully disconnected and made no difference.
It might also be worth mentioning the car is auto as well. Oh, I also pulled the air filter out and tested with no change.

Leroy Peterson
28-05-2017, 08:02 AM
I'm not familiar with how loud or what frequency car interference is usually, but I'm thinking something to do with the drivetrain. since its same noise regardless of gear, at certain rpm. around the flywheel area maybe? im not sure. I woudl take it to an auto workshop and spend $50-100 on a diagnosis.

08-06-2017, 11:44 AM
So to answer this question, the mystery noise was my alternator going bad.

08-06-2017, 05:52 PM
How did it end up manifesting itself ? failure of the alternator regulator with flat battery or through further diagnosis ?

08-06-2017, 10:00 PM
I'm not entirely sure which part of the alternator failed, however it stopped outputting any current and threw the lights on the dash. I'm not going to bother with a postmortem. Could be that the brushes wore out, regulator failure, an issue with the windings, I don't really know. I'd say it suffered at the hands of the people that stole the car last month, as you can imagine they weren't very kind to it.

So I drove home on the remaining battery power, bought a new alternator through a mate's cooldrive account, fitted it tonight, solved :)

Leroy Peterson
09-06-2017, 10:31 AM
Awesome, good it got sorted