Did you know that a (most likely) failing alternator has these symptoms? I didn’t.

"mazda616" (mazda616) 07/12/2020 at 07:11 • Filed to: Jolene the Sunbird

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Jolene has developed a whine. It increases and decreases with engine speed. There’s also a slight burning smell.

My grandfather and I did some investigating. It’s not a belt as neither the serpentine or A/C belts are slipping. In fact, I just replaced the A/C belt yesterday. However, after a one mile drive, the alternator was scorching hot. Too hot to touch, even. And, the noise seems to be coming from that area - as well as the smell. The smell didn’t develop until the noise did, either.

So, I’ve ordered a new alternator as this one is pretty old. I am 99% sure that’s the issue based on my own research and watching videos of other failing alternators and the various sounds they produce. What’s odd is that the alternator is still charging okay. All of the admittedly few electrical accessories the car has still work fine. But, what I believe has happened is the bearings inside the alternator itself are going out. The noise is from them and the smell is the alternator literally overheating itself to keep spinning.

I’ve parked the car until I get the new alternator on as I don’t want the current one to seize and take the belt along with it.

I’ve attached a video of the sound. Sorry in advance that the video is not the best. It was 14,000 degrees outside and I was already hot and frustrated.

I found a few videos on YouTube that also match the sound Jolene is making.

pip bip - choose Corrour > mazda616 07/12/2020 at 07:33

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is it too hot to touch?

I like cars: Jim Spanfeller is one ugly motherfucker > mazda616 07/12/2020 at 07:36

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If it charges fine and a bearing is just done, you can rebuild it. If you’ve never done that, you should try it. It’s fun!

mazda616 > pip bip - choose Corrour 07/12/2020 at 07:37

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Yes. And that was after a one to maybe two mile drive.

pip bip - choose Corrour > mazda616 07/12/2020 at 07:37

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problem found. 

Exage03040 @ opposite-lock.com > mazda616 07/12/2020 at 07:42

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FYI Mazda, recommend checking if the wiring is corroded.

My beater did the same thing and I wiped out a brand new reman after an hour of swapping it over; found the alternator ground was no good .

Urambo Tauro > I like cars: Jim Spanfeller is one ugly motherfucker 07/12/2020 at 08:16

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Just did this on my car! Easier than I thought. Shoulda done this a long time ago on previous vehicles that needed alternators...

Mine w asn’t even having any charging problems either. Just bearing noise. Turned out to be the front bearing, but I replaced the rear one too anyway, as well as the slip rings and brushes/voltage regulator assembly since they were all included in the kit. Cost me about $40.

Nom De Plume > I like cars: Jim Spanfeller is one ugly motherfucker 07/12/2020 at 08:19

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How over the top was your bearing upgrade?

Merfthemadmauler > mazda616 07/12/2020 at 09:04

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I replaced mine when it made that bearing wearing out  sound. There were no other symptoms. Needed the vehicle for work so I working on an alternator was not an option timewise.p

Merfthemadmauler > Merfthemadmauler 07/12/2020 at 09:06

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I should proofread.

TheRealBicycleBuck > mazda616 07/12/2020 at 09:22

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Sunbirds are hard on alternators. My wife’s ate three of them before we sold it. The third one was what cemented my relationship with my wife.

We were dating at the time and she told me that her dad would be coming up on Saturday. It was a six hour drive, so I asked why he would be coming. He was coming up for the day to change the alternator on her Sunbird. That’s when I put on my hero mask and cape and stepped in to save the day. It’s an easy swap. It took 10 minutes.

When I finally met her parents, her dad shook my hand and thanked me. My wife told me after we were married that it was the first time her father had ever shaken hands with one of her boyfriends. T hat was his seal of approval.

AMGtech - now with more recalls! > Exage03040 @ opposite-lock.com 07/12/2020 at 09:41

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What happens is the electricity finds a new path due to high ground resistance. One option is through the bearings and case to the engine. But the electricity will arc through the bearings, and the arcing creates pitting on the beating surfaces.

This isn’t super common and kind of depends on how the ground circuit is setup. It’s more likely if the alternator had it's own dedicated ground, rather than sharing a main ground with the whole engine or even just the starter. If it's shared, you'll usually get a slow crank or weird fault codes before the alternator dies.

AMGtech - now with more recalls! > mazda616 07/12/2020 at 09:47

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Alternators are neat. They can stop converting to DC and send AC into the rest of the electrical system. They can make a few different noises. They can seize. They can cause a parasitic draw. They can kill an engine control unit (LIN bus controlled charging system; extremely rare issue). They can overcharge and kill plenty of sensitive components or blow fuses.

Draws and AC voltage are the weirdest end most interesting ones I've ever seen.

someassemblyrequired > mazda616 07/12/2020 at 12:02

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if it’s not recent, the battery is probably on the way out too, tends to coincide with alternator failure on those cars , so it’s definitely worth a check