Smells like a bad alternator

[Darrell]

While driving started noticing louder than noise that sounded like belt driven accessory. First though was power steering pump.

Parked car, popped hood. Burnt smell and very hot alternator. But not sure how hot it normally is.

Turn off car. Sits 15 min. Measure battery voltage. Low 12.2 volts.

Connections all good at battery and alternator. Start car. NO change in voltage. So no charging.

Is there any universe in which this is not a bad alternator? Battery is about 4.5 years old. 1997 Toyota Camry but only 100k miles. These parts don’t often go bad on Toyotas. Bad battery burn up alternator? Or just 20 year old part ready for a rest? 😉

Topic

[Steve Klein]

You should be seeing some charge at idle (about 13V) if there is any electrical load. If you rev the engine and you see it attempting to charge at a higher RPM that would confirm a bad alternator. The brushes are probably burnt up and that is what you are smelling.

[Darrell]

Realized there was a salvage yard 10 minutes from my office so got a “new” alternator on way home. Before swapping out I reconnected multimeter. Bumped throttle and voltage did go up past 14 but then I turn on all the electrical stuff I could. Voltage dropped down to 11.5 and stayed there even with me holding throttle. Swapped out alternator and now at idle with full electrical load voltage holds steady at 13.5+ . All is well. (For as long as the junk yard alternator lasts. Ha!)

[Author]

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