I have a low pitched whine/vibration that I can hear sitting in the driver's seat that get's louder with any increased electrical load - turning on headlights, power windows, power locks, etc. I can't hear the noise in the engine bay, but when I put a stick on the alternator with the car running and then turned on the lights, I could definitely feel the stick start vibrating.

Is this a pretty clear bad alternator? Belts are less than two years old, and I replaced the alternator. brushes at the same time. Can you repair an alternator or just replace? Is OEM the only way to go here or not necessarily? Thanks!

Could be that the pulley is bad and not the alternator itself? I've never heard an alternator make noise otherwise but I could be up my own ass. If you're not losing power when idling I would think perhaps this would be the more likely culprit
I'm fairly sure you can get new pullies and swap them out but not positive at all. There definitely are alternator shops out there that will rebuild units from top to bottom but I don't know if it would be all that recommended to send in some totally standard unit - I guess it would depend on their pricing vs price of a new alt, at that point
Personally, if it's old, I'd just replace it - maybe keep it around as a spare if you really wish. Time for a new piece in it's place to last another 20 years

Alternator brushes usually last 180k to 200k miles in average. I would verify it's the alternator via a mechanical stethoscope or a rubber hose.

I mostly go denso remfg from rock auto if I want to replace them. They will want you old one sent back for a core charge. As denso is the oem mfg. Plus they are alot more affordable then the oem toyota ones if you can still get them new.

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Check your grounds are good.Check the alternator is properly grounded. An electrical whine is usually a bad ground.
The alternator is grounded to the chassis so check the bolts are good and tight.

Agree that a Denso remag is should be a good choice, some say the Toyota remag is better. I bought a Denso remag for mine, installed it, then realized the Toyota remag (from discount online dealer) was only ≈$30 more. The Denso has only been in a few months, no report on durability.

I used Denso remfg for years. They are just as reliable as oem. Being it's literally just a Toyota sticker difference. You saved $30 bucks.

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Do you have a volt meter to measure voltage with the headlights on at idle?

I had that noise, but louder, and it was a bad rectifier assembly. It run 13.8 volts with nothing but the radio on. Anything more than that the whine would get louder and the voltage would fall on its arse.


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Interesting - I've never heard of this. last night I went and checked any wires coming from the alternator - you have the one on the side and the wiring harness in the back, but they both seem to feed into a plastic conduit that heads...elsewhere. Do you happen to know where this ground meets the chassis?

I do - I will give that a look today. Thank you.

What is a rectifier? Part of the alternator?

I ordered a reman'd alternator from McGeorge Toyota. I mostly trust Denso but I know not all Denso are created equally, so that scared me into spending the extra 50 or 60 bucks to get one from Toyota. The original lasted over 20 years and 245k miles.

Am I correct in assuming the possibility that I could have a bearing going bad in the alternator that may not be affecting the voltage? In other words, if my voltage checks out ok, that still doesn't totally rule out my alternator needing replacement, right? I am confident the noise is coming from the alternator when under extra electrical load, so I'm thinking I should replace it regardless of how my voltage reads, but my logic here may be flawed.

Yes the bearings and the interals can get noisy. Some of the forum users rebuild them except if the armature is damaged then that's mostly a replacement.

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You have to buy the denso from the reputable sources. As eBay and Amazon are mostly full of counterfeits. Especially if it's a great price...

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It’s the diode block under the back cover. I documented replacing it and brushes in my Build and Repair thread.


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I actually had my grounds on the bridge rectifier glowing at night on a OEM Toyota denso in a camry once. I saw that and bought a remfg alternator because the nuts were rusted and slight melting from the ground going bad... so yes it can be more then shaft bearings going bad..

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The alternator is grounded by its mounting points to the motor. The engine is grounded to the chasis. Check the grounds by the abs diagnostic port on the plenum. There is one close to the oil filter at the bottom on the driverside.Then one on the fender wall by the battery.