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Discussion Starter #1
Hope y'all are having a good holiday season.

So my 2008 Rav4 4 Cylinder basic model started making whinny sounds from where alternator/AC compressors are. That started last night, and today, the battery light came on while driving and I drove home and opened the hood. There is bits of smoke rising up from area near the alternator, and in a few minutes, the battery drained completely such that even the dash console doesn't light up with the key in.

Is it common for failed alternator to cause short circuit to drain the battery so quickly and completely? Is this a common failure mode for alternator?
 

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Discussion Starter #2
Some update:

So unplugged the alternator wire and connector. The battery voltage goes back up to about 8V. The resistance between the alternator's wire terminal and the ground is zero - so seems an internal short within the alternator.

So here are some follow-up questions:

1. How common is it for an alternator to go so quickly, from start making noise to burning out/shorting, within two days?
2. Would you suspect something else could have caused the alternator fail? With the alternator unplugged, there is no obvious short circuit.
3. Recommendation for replacement. New or rebuilt? How tough is it to rebuild it DIY?

BTW, a note of thanks to junebug for sharing his document stash - been very handy.
 

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Wow this is an odd one. The whine would be from it trying to push high current into whatever part is developing the short. Could just be a failed diode but with all the cooking it has done I'd replace it. A new one online probably isn't much more than a reman.
 
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That "Failed alternator" is a rather strange scenario. My purely a theory - f the alternator had an internals short that should have blown the alternator fuse, and in any event, suggest that it be checked. Location - per this thread: http://www.rav4world.com/forums/99-4-3-mechanical/98257-how-many-amps-my-alternator.html#post993953 Alternator deaths in some Kawasaki Vulcan motorcycles are caused apparently at least in some cases by insulation which is improperly applied or in too small amounts in what would be a field coil or a diode which has gone bad in a car alternator, resulting in a short, and generally is signaled by a loud whine emanating from the alternator location, possibly caused by mismatched current polarities because of the short.

That the battery was drained and in such an apparently short time is a puzzler. An alternator short possibly could occur without blowing the alternator fuse if the short wasn't a dead short involving a smaller gauge (thicker) wire, such as a leaking wire from worn insulation on a field coil. But in that instance the current drain on the battery should have been rather slow. Perhaps the alternator whine was the indicator that a slow drain short had occurred and that was the starting point for current being drained from the battery.
 
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Discussion Starter #5
Is that odd?

Found the following while looking for replacement parts.

"OEM" alternator the dealers sell are reman part, going for bit over $500 local and bit over $400 online. An alternative is a reman denso alternator for $200 online.

As for belt, the dealer part goes for over 60, but gates/dayco/bando goes for less $20.

Any recommendation on which to go for? Also, any tip on doing the work?

Edit: Checked the fuse box and no fuse were blown. It's a base model with no special options. The alternator is rated for 100A and the fuse is 120A.
 

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my 2007 4 cylinder alternator failed early at 70-80k miles. i was surprised because my other toyotas have over 100k miles without alternator problems. i was thinking it was the battery but it was my alternator. it should be over 12v when it's running. i bought a remanufactured denso alternator for $140 after core charge return on rockauto.com. for the serpentine belt i used a goodyear gatorback and never had any squeeks. take off the front passenger tire and subframe brace to remove the serpentine belt. the serpentine belt tool rental from autozone works well. should take around 3 hours or less start to finish. should be faster if you've done the serpentine belt before.
 

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My i4 alternator failed at 65K miles. A little too early in my books.
At least winter was just starting. Would have been a million times worse in -5F with my 2 kids in the back.
 

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Discussion Starter #8
Thanks for the tips.

Removing/installing the serpentine belt while relieving tension seems bit handful. Is it a one-man job with the belt tool?
 

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Thanks for the tips.

Removing/installing the serpentine belt while relieving tension seems bit handful. Is it a one-man job with the belt tool?
Check youtube out and you should get those answer.
 

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My i4 alternator failed at 65K miles. A little too early in my books.
At least winter was just starting. Would have been a million times worse in -5F with my 2 kids in the back.
Can't help with the alternator, but here in MinneSnowta we keep a catalytic heater in the back for emergencies.
Best for the New Year,
Pico
 

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Discussion Starter #12
I was about to order the parts from rockauto, but a very silly person insisted to have the job done by a local mechanic. Since this stupid person is the primary driver of the vehicle, I had to defer.

It took them less than two hours to replace the alternator and the v-belt. The new belt is of gates brand, but the alternator is no-name brand by some local outfit that rebuilds alternators - hope it will hold up.

Costs me $300. Factoring in 1-2 hours of labor, it seems reasonable.

Thanks all for your help.
 

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Thanks for the update. Sometimes we never hear.
I just wonder if the primary driver sees your posts.
 
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