You may see the headlights and dash lights flicker at an idle. You may hear unusual noises coming from the alternator when the engine is running.
There are several signs that an alternator is going bad. A few signs are dim lights, smell, warning lights, and a dead battery.
A few symptoms and obvious signs of a bad alternator are the battery not charging, dim lights, and a warning light.
When your battery does not get charge.
If bearings go bad they will "squeal"
There are a few reasons why your alternator might keep going bad such as rusty latches under the car. You may also have leaks, dents, or parts that need to be replaced on the vehicle that are effecting your alternator.
Normally this is the bearings going bad.
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Alternator is going out? battery is going bad?
A bad alternator will make whats called a whirring noise. It could also make a low growl. This is just the bearings going bad. If your alternator is not supplying any power, it has nothing to do with noise typically.
The diode in the alternator is probley going bad, Check charging system. And replace alternator.
There could be many reasons your battery is going bad or your belt is off or you have a bad alternator.
Usually it means your alternator is bad or going bad.