Car Alternator Bearing Noise: 6 Things You Should Know

Altenator bearings can last a long time.

But once in a while, as the mileage covered by you may hear increases, you may hear the dreaded whirring noise under the hood coming from the alternator.

It is a worrying sound considering that it comes from the alternator the supplier of electric power to the car accessories as you drive!

So in this post, I will cover the other symptoms of a bad alternator bearing, possible causes of damaged bearings, how long you can drive with a bad alternator bearing, and whether it can be replaced.

1. Symptoms of a Bad Alternator Bearing

Whirring, grinding, or high-pitched sound

A car alternator with a bad bearing usually produces a whining or high-pitched sound.

It can appear in several forms- grinding, squealing, and rattling instead of the silent hum from a properly functioning alternator.

This sound will usually be heard when the car is started and the alternator starts running.

It is not always constant and may stop as the engine speed increases or reduces and may be able to drive the car properly.

If you continue driving the car over a period of several days, weeks, the whirring sound can progressively become worse.

It may be heard constantly and in extreme cases, the alternator can become extremely hot giving off the burning smell from the friction in the bearings.

2. What Causes Alternator Bearings to go Bad?

The car alternator bearings can go bad because of several reasons:

A long period of usage of the alternator

Alternators have moving parts prone to wear and tear over time.

While some alternators work for a long time without any issues, some have bearing failures after the car has covered several tens of thousands of miles.

Be particularly careful with alternators that have undergone repairs previously – these are not usually covered by warranty and their service life tends not to last as long.

Drive Belts tightened too tightly

There are cases of alternator bearing failures that have been attributed to the drive belts being tightened too tightly.

The bearing failure from this may not happen immediately but can happen over time.

So, if you are replacing a drive belt, make sure it is fitted right with the correct tension for your alternator to minimize the likelihood of bearing failures.

Alternator is exposed to Water

Exposing the alternator to water, especially driving through high waters not only has a negative impact on the car’s electrical system, but it is also bad and can lead to premature failure of the alternator bearings.

3. How Long Can You Drive ? | Alternator with Bad Bearing

There is no telling how long or how far you can drive with an alternator that has a bad bearing.

It really depends on whether the fault with the bearing is still in the early stages, how often you drive or whether the fault is in advanced stages.

For an early stage, mild bearing noise problem, you may be able to drive for days, weeks, or even longer. Beware of the risks though.

While the noise might be on and off initially, do not be fooled, the problem tends to get worse with time.

Continuing to drive the car in this condition is extremely risky and can lead to overheating smoke, and permanent damage to the alternator from the friction.

When the noise is constant, a sign that it is in advanced stages, you cannot and should not attempt to drive – the car requires immediate attention.

So, if the alternator makes the whirring sound, arrange to replace it with the alternator or bearing as soon as possible.

4. Can You Stop the Noise in Car Alternator Bearing?

Probably the most effective and long-lasting way to stop the bearing noise is to replace the bearing or alternator altogether depending on the extent of the damage.

This way you are confident that your car will be able to start every time without the worry of being stuck in the middle of nowhere.

5. Car Alternator Bearing – Can you Replace?

If the car alternator has worn out bearings, these can be replaced for a considerably lower cost than replacing with a completely new alternator.

Make sure though that the diagnosis and repairs are conducted by a competent auto workshop to minimize the likelihood of a repeat of the problem.

You can find the bearing part number off the damaged bearing.

Make sure to replace it with the match and use proper tools or else you risk damaging the alternator.

Beware though that with repair, there is no or limited warranty and if not done properly, your car can fail again quickly.

6. Risks of Driving with a Noisy Alternator

Whereas you can start and drive your car even with a noisy alternator, beware of the risks below that doing so poses.

A car engine can stop in the middle of nowhere.

The noisy alternator problem can become worse at any time leaving your car without a power source for the accessories and to charge the battery.

Is it worth the risk of continuing to drive with a noisy alternator? This is worth considering.

incurring the replacement cost of a new alternator instead of fitting a cheaper part

Continuing to drive the car can lead to overheating and permanent damage to the alternator.

So, what would have been a part replacement cost of $50 or less can instead become several hundred dollars worth depending on the type of alternator.

You may also want to read the post: 4 Most Common Risks you face while driving a car with a bad alternator

To summarise

An alternator with a bad bearing problem usually shows up as a grinding, high-pitched whine from under the hood.

Be sure to confirm that it is from the alternator as there are a number of components that can cause it.

Damage from the alternator can come from age of the alternator, belts tightened too tightly, or even exposing the alternator to water.

If the problem is in the early stages, you may be able to drive the car for a while, days, weeks, or longer but beware of the risks.

You can get stuck in the middle of nowhere because of a malfunctioning or damaged alternator.

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