High pitched whine

BlacksonAudio

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I’ve been chasing a running hot/overheating issue for a month now. I think I read somewhere in one of these threads that it’s a hydraulic pump? Or the fans not getting fluid or enough fluid. I’ve read so much it’s insane
 
Believe it or not, I had a high pitched whine last fall, it turned out to be an alternator bearing going out. Took me several days to pinpoint the noise.
 
If I remember correctly in your facebook video, are you referring to the REALLY high pitched whine? Like 4000 and 7000Hz and more of a sine wave tone than a whine? Plenty of test tone videos on youtube to compare if you don't have a tone generator/app. I was thinking about this while cruising back from the Ford Nationals yesterday. I was enjoying the new mufflers so I didn't have music playing and I could hear it in the car. Very subtle and easily washed away by road noise if anyone was near me. I noticed I could get it to step up and down with little taps of the throttle (it changes in a couple incremental steps, so not pulley whine). It's been there and constant in the 6+ years I've had the car (2002 V8)

I had an idea - what if it's the hydraulic pump solenoid vibrating with the PWM signal? Maybe something about the PWM control scheme of the alternator? I think the solenoid would probably be a steady 100Hz tone of varying sound since its a 10ms fall time signal, but both of these parts are unique to gen 1 and could explain why so few know what we mean. I do find it interesting you didn't notice it on your gen 1 V6.

I'll try to take a ride with forscan and watch the gen(erator) and fan PIDs to see if one changes with the tone. Maybe the aux pump? Or I'll have to poke around with a stethoscope
 
Well since you arr having an overheating issue... are you sure it isn't the fan spinning at high speed... trying to cool down the engine.

The fan at max speed can sound like a jet engine.

Is your whine consistant... or does it vary with engine temp? Or... does it vary with engine RPM?
 
Thanks guys. There was an thread on here about changing the actuator. Said once you refilled the reservoir if you hear a whine start over. Like the fan motor or pump wasn’t getting enough fluid... still trying to find that thread
 
My alternator made some loud and strange sounds a day or three before it failed completely. However, the sounds were louder at idle, and changed (both frequency and amplitude) with the electrical loading.
 

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