Whining alternator driving me crazy, tried everything

[MichaelSE]

My alternator whines like hell. I have been dealing with this for months, and I'm sick of throwing time and money at it, hopefully one of you can point me in the right direction.

The whine goes away when the battery charging cable is disconnected from the alternator.

It's a whine from the engine bay and does not come through the speakers.

Here's what I've tried so far:

1. 2 new alternators. The one that was in the truck when I bought it made the lights flicker, but didn't whine. I replaced it. This one whined. I believed it to be defective so I got it replaced by Amazon. The replacement does the same.
2. New battery. Mine was rated for 730cca and it came in at 640, so I replaced it. No difference.
3. Disconnected the connector near the battery that controls the variable charging system, as suggested in another thread. No difference.
4. Took apart the main 175A fuse box and cleaned all connectors, put dielectric grease on them.
5. Followed the positive and negative battery cables as far as I could looking for fraying. They look fine.
6. Pulled the belt off to check the pulley bearings on both alternators. They spun freely.
7. Used the multimeter to check voltage between battery-block, battery-body, body-block all 0.0 volts.

The battery reads a pretty consistent 14.8 volts while the engine is running. The alternator puts out a very consistent 14.8 volts from the stud. When the control wire is disconnected, it puts out 13.4-13.5 volts.

Any ideas? Thanks in advance.

 

[sumo]

What's the brand on the alternator? Had experience in the shop were customers installed aftermarket alternators for a complaint whine. Turned out it was the brand of alternator they chose. Installed oem and problem went aeay

 

[MichaelSE]

It's a Remy International alternator. Both were brand new, not reman. Maybe they just make shit alternators. They won't replace this one and I won't spend another $120 on a new alternator. I think I might go to the scrapyard and pull a used alternator off an NBS Silverado and try that.

 

[Big Homie]

When I had alternator whine my alternator was going bad, and (more importantly) couldn't handle the load placed on it (vehicle load + car audio system). It's possible those new alternators don't put out enough power in the right rpm ranges for you, new or not. This is sort of confirmed when you remove the battery charging cable and the whine goes away. It's at that point all the electronics are being run off the battery. If the alternators are whining with all auxillaries off (headlamps, hvac, radio, etc.) then it's likely putting out lower power than stock.

 

[MichaelSE]

When I had alternator whine my alternator was going bad, and (more importantly) couldn't handle the load placed on it (vehicle load + car audio system). It's possible those new alternators don't put out enough power in the right rpm ranges for you, new or not. This is sort of confirmed when you remove the battery charging cable and the whine goes away. It's at that point all the electronics are being run off the battery. If the alternators are whining with all auxillaries off (headlamps, hvac, radio, etc.) then it's likely putting out lower power than stock.

I'm just worried that something else, like a bad ground, may be causing the issue and it will just reappear in the third alternator I throw on. My Suburban is stock with no system or extra lights, and the alternators were 160 amp which the RPO calls for.

 

[MichaelSE]

I'm going to bump this back up since I am still dealing with this issue and it is still driving me insane. Any help would be appreciated. At this point I have a new battery (12/2017 manufacture) and I'm on my 4th alternator, an ACDelco OEM, and it is whining -- in fact, it's both whining and making the lights flicker, and I am at my wits end with this. The dealership says both the battery and alternator test out fine. Someone please help.

 

[Doubeleive]

I might suggest throwing some old school fixes at it like a ground loop isolator and/or ferrite. it's not right fix but it should work.

 

[Doubeleive]

something like this
https://www.ebay.com/itm/LINDY-Ferr...979778&hash=item5b33cd9ff6:g:2KoAAOSwR6RaCYS4

 

[Doubeleive]

and have you tried new ground cables or doing the "big 3"

 

[RED TAHOE LS]

Alternator whine is caused from MAX charging rate the BATTERY is asking for.

The load control connection was designed for GAS MILEAGE just like my Honda has. Unlike your vehicle, my Honda has a ELECTRONIC LOAD DETECTOR that does the same thing, it tells the alternator when to add more charge to the battery, which in turn helps mileage. How do I know this, I had a battery problem and changed the little detector, problem solved.

That little HONDA detector was located in the fuse box (under hood) about the size of a book of matches and black in color. You should trace from the cable you talked about and locate the control unit and replace it. JMHO and good luck.
David g......