Alternator Noise

[Wytchdctr]

Before I spend three hours at the dealership to hear it is normal... I thought I'd ask here.

Getting a little alternator whine at around 1200 to 1500 or so RPMs - but I can only hear it if I am next to a building or have someone rev it a bit and I'm under the hood. So it isn't exactly loud.

Need to worry or normal Ford things?

1k miles

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[P. A. Schilke]

Before I spend three hours at the dealership to hear it is normal... I thought I'd ask here.

Getting a little alternator whine at around 1200 to 1500 or so RPMs - but I can only hear it if I am next to a building or have someone rev it a bit and I'm under the hood. So it isn't exactly loud.

Need to worry or normal Ford things?

1k miles

Hi Patrick,

The whine might not be electrically induced but is a noise of the alternator drive belt... When you are using a sound wall like the side of a building you have to be careful as there are all sort of noises that have no bearing on the normal vehicle operation. If you had a sound recording and an FFT analyzer, you could determine the noise frequency but in absence of this, purchase a cheap mechanic's stethoscope and discard the metal probe and diaphram...using just the tube with the ear pieces in your ears, search the alternator as this is very directional and should show you the source of the noise.

Back story, I got reports of a noticeable whine on a customer vehicle and I tracked it down to the alternator. Replacing the alternator fixed the problem, but what was the root cause, so I took the offending alternator and installed on one of our prototypes...it whined just like in the other vehicle. So off to Ford Electrical for their investigation...what we found was the laminated plates at the center of the two cast halves of the alternator were not tight and as such were vibrating and making the whine noise. Never again experienced this and we regarded this as a poorly constructed component, not a systemic issue. It did result in an investigation of the product line to ensure the rivet setting machine was doing its job.

So if it were me, I would just drive my vehicle and if the sound becomes louder, take it to the dealer under warranty for investigation....JMO...

best,
Phil

 

[Wytchdctr]

I would just drive my vehicle and if the sound becomes louder, take it to the dealer under warranty for investigation....JMO...

best,
Phil

Thank you for the detailed reply. I'll let it ride. Got a few more miles on the odo before I have to replace it myself. I will report back if it becomes a real problem.


That weirdly specific rpm range could be something more harmonic than a sign of doom.

 

[Wytchdctr]

Got a chance to isolate this looking for my chirping noise (another post covers others with the same bird noises). It is the trans pump that is "normal" for this trans. Alternator is fine.

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