New ( rebuilt alternator) whining & running hot after only 200 miles

My1995 toyota camry XLE V6 alternator has developed a distinctive low pitched whining sound after only 200 miles of use. The alternator is a rebuilt one from Advanced auto parts. It also becomes very hot to touch after only several minutes after start up. There is also a distinctive “hot” smell from it. The alternator has a lifetime warranty which is ok but if anyone has any ideas as to why it would be doing this so soon after installation I would like to hear your suggestions.
I replaced the battery at the same time as the alternator as it was “shot”. It was a “2 year” battery that lasted 3 years and I decided to replace the alternator at the same time. It was the original Toyota alternator and was 28 yrs old and still working ok but I decided to give myself some security by replacing it. Looks like I “screwed” up there. Anyway any suggestions would be much appreciated as I really don’t want to be changing alternators every 200 miles even if they are “free”.The car has 130, 000 original miles and runs normal otherwise

Defective part (it happens a lot), bearings bad, wrong amps output… I would just take it back and swap it out asap…


Concur w DMP above, a faulty rebuilt alternator seems very likely. Faulty rebuilt parts a pretty common problem by reports here. I’m just a driveway diy’er, only replaced maybe a half-dozen parts with rebuilt parts over the years, and I’ve experienced two faulty parts store rebuilt starter motors myself, both failed right out of the box. So you aren’t alone by any means. I expect what happened, the rebuilt alternator’s replacement bearings were damaged during the rebuild process. An inexperienced tech might have pressed a new bearing onto the shaft incorrectly.

I expect you already know this, but suggest to hold on to original oem parts when purchasing replacement rebuilds, just pay the core fee yourself. If you did that and still have the original oem starter motor, take it to the local well-recommended auto-electric shop and ask them to rebuild it for you. A little more expensive probably, but much more likely to get good results.


Thank you for taking the time to respond.
Good idea about paying the core charge yourself and keeping the OEM part. I suppose you live and learn, but good to know :+1:

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Likely a bad part. Return it and spend the extra bucks on a new one if they offer that. Get the premium one, not the cheaper one as well.

I am not always a huge fan of reman equipment, especially in my IT line of work. Of course I never see the success stories, only the failures but these usually cost the customer far more than if they had just bought new in the first place.

Factory remans are usually a solid bet. So if you could buy a Toyota reman done by Toyota, you would be better off. This applies for Ford Motorcraft, etc. as well offering reman options.


There could be a shorted winding in the alternator. You could have injected some grease in the bearings of the old one and kept going with it. Maybe one of the diodes in the rectifier is shorted.

You may want to consider injecting grease in to the bearing in the A/C compressor. Last year my 30 year old R12 Toyota one started making noise and I didn’t catch it soon enough. I greased it but it has a bit of a strange sound in it now.

That car has probably never broken down on you has it? Is the green D for drive indicator light burnt out yet?

This may be more work than you want to do, but if I had lost the OEM alternator, I would get a used OEM one from an auto recycler. If I had any doubts about it, I would take it to a local auto electric shop and ask them to test it and refurb it as they deem reasonable.

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Thanks for all the responses👍

I had the alternator tested on the vehicle at the store where I bought the part. At the time it was not making any unusual noise. The car had not been used since my last post. The result was excessive “flutter”. That was the display on the tester. Otherwise it was running ok and charging ok. They did not know what the reading meant and were honest about it at least. They suggested just swapping it out under the warranty on the alternator. Of course I will do this anyway but I’m just curious as to what excessive “flutter” is?

I forgot to mention that the alternator drive belt is in excellent condition, runs quiet and is adjusted correctly.

Probably referring to excessive ripple. Sometimes caused by leaky diodes in the alternator.


Ripple is what I was thinking of also, just couldn’t think of the name at midnight last night… :grin:

You shouldn’t be up that late! :slight_smile:

Whether there is “Ripple” or “Flutter”, the only time I have ever seen these two words used together is when I’ve seen a Butterfly Flutter over a pond and its winds create a Ripple in the Water… L o L . . .

Is this all “double-speak” for the voltage bouncing around rather than having a steady output?

That seems like a good approach. One the the jobs the alternator is responsible for it to convert the electric current it generates from alternating current to direct current, using gadgets called diodes. If it doesn’t do that correctly the voltage will vary with time, which might appear on an o’scope display looking sort of like a butterfly wing fluttering. It should look like a steady horizontal line. Electrical engineers would usually call it “voltage ripple”, but it’s the same thing.
The battery does part of the job of reducing the ripple , so if the parts store test you mention above was done with alternator still in the car, it is possible the problem is the battery, not the alternator.

Interesting historical fact. Diodes are a relatively recent invention, and only became available for automobile use in the early 60’s. Before that cars used “generators” rather than alternators. Generators were configured with a manual switching arrangement, which performed the diode function. The main problem w/generators wasn’t the switches were unreliable so much, but that they didn’t output enough electrical power when the engine was running at a low rpm.

Ripple …Diodes rectify the stator’s AC current into DC. Although this happens, a small AC voltage still appears at the alternator’s output terminal. When properly displayed on a scope screen, this AC voltage has a rippled appearance, consequently, it’s called alternator ripple. if the diodes are leaking more than spec, it is called excessive ripple…

I think Flutter has more to do with an alternator with an OAD (Overrunning Alternator Decoupler, think of a sprag/one way clutch) Pulley and the belt loosing tension and regaining tension letting the belt sort of flap/flutter…

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Sounds like a defective rectifier.