Bad Alternator Bearing Symptoms (9 Things To Be Aware Of)

If you own or drive a car, then it’s likely you’d know to look at the alternator if something doesn’t work.

While it’s true that a faulty alternator may affect cars, not many people know that a part of the alternator, called the bearing, can be the reason for this. Here’s what I found!

Bad Alternator Bearing Symptoms

Some symptoms of a bad alternator bearing are loud noises, burning smells, or even dim internal and external lights. A malfunctioning alternator bearing might also prevent your car from starting or cause it to stall while you’re driving. A battery that has been discharged could be an indication that your car’s alternator bearing is broken.

To learn more about the signs of a faulty alternator bearing, keep reading!

1. Broken Alternator

One of the more common signs of bad alternator bearings would be a damaged alternator.

Generally, a pair of needle bearings in the alternator allows its components to spin.

Additionally, these bearings reduce friction within the alternator, thus enabling efficient energy transfer and protecting the alternator’s parts from damage.

However, the bearings may wear down from exposure to heat and grime, which can result in the rotor seizing and ultimately the alternator failing.

As such, a broken alternator may be indicative of problems with its bearings.

2. Dead Battery

Aside from a broken alternator, a discharged battery may also be a symptom of bad alternator bearings.

In this situation, the battery takes over providing power to the car when the alternator fails due to faulty bearings.

However, since batteries aren’t designed to power your car for extended periods, this could lead to the battery running out of power.

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In other words, even if the battery wasn’t the problem initially, bad alternator bearings may cause your car’s battery to die.

3. Warning Lights on the Dashboard

Additionally, related warning lights may indicate a problem with the alternator and its bearings.

Usually, some warning lights on your dashboard will let you know if there are any problems with your car.

Depending on your car’s make and model, the light may show “GEN,” “ALT,” or a battery symbol to signal alternator issues.

As a result, if the warning light comes on, the alternator may not be supplying enough power to charge the battery because of faulty bearings.

Therefore, those warning lights may be indicative of damaged alternator bearings.

4. Dim Interior and Exterior Lights

In addition to my points above, another symptom of bad alternator bearings is dim cabin lights, headlights, and taillights.

For instance, bad alternator bearings can affect the amount of available electric power available to power the interior and exterior lights on your car and make them dimmer than usual.

Moreover, it can be dangerous to drive at night or in cases with low visibility with dim headlights.

As such, it’s important to get the alternator and its bearings checked immediately if you notice dim lights in your car.

5. Electrical Components Aren’t Working

Electrical Components Aren’t Working

The alternator bearings may also cause the electric-powered parts of your car to not work, and you might not realize this until you put more stress on your car.

For instance, most cars come with power locks and windows; if yours stop working, it can be because of an issue with the alternator bearings.

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Additionally, the same is true of your car’s other electrical accessories, such as the stereo and accessory ports.

Thus, these problems can point you to the alternator bearings.

6. Burning Smell from the Engine Bay

In addition to my points above, burning smells can also be a symptom of faulty alternator bearings.

For instance, if it smells like burnt wires then it’s likely due to the bearings causing the alternator to overheat or burn.

On the other hand, if it smells like burnt rubber, the alternator belt may have broken from the excessive heat from the alternator bearings.

As such, if you catch a whiff of any burning odors from your car, it’s best to have it checked right away.

7. Odd Noises

Aside from burning odors, strange noises may also be a sign of alternator bearing trouble.

Occasionally, whining or knocking sounds can be associated with the alternator bearings coming loose from the alternator.

Additionally, grinding or squeaking noises, either of which becomes aggravated when you accelerate your car, can mean that the alternator bearings are bad and need replacement.

As such, these noises may be indicative of problems with the alternator bearings.

8. Stalling Engine

In addition to the points above, your car may also have damaged alternator bearings if it frequently stalls.

Generally, the battery won’t be able to supply enough energy to start your car’s ignition if the alternator is unable to supply electricity to it.

Additionally, the alternator may not be providing the spark plugs with enough power to keep the engine going, which causes the engine to stall.

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Therefore, these issues could be a sign that your car’s alternator is malfunctioning.

9. Car Starting and Immediately Dying

Aside from stalling while you drive, bad alternator bearings may also be causing your car to die shortly after starting.

In this case, your car could die after starting even if your battery has enough power because the alternator has been damaged by faulty bearings.

As such, your automobile could erratically stall while driving or just after starting if your alternator bearings are damaged.

To know more, you can also read our posts on bad water pump symptoms, bad wheel-bearing symptoms, and BMW bad alternator symptoms


There are a few warning signs to look out for when you think the alternator bearing is damaged, such as a dashboard warning light and strange sounds or odors.

The alternator, and in turn the ignition system, might suffer significant damage from a bad alternator bearing as well.

As such, it’s essential to get the alternator and its parts inspected by a reputable expert to address any issues.

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