Why a Car Alternator Belt Breaks (3 Common Causes)

A good quality car alternator belt can work reliably for many years enabling your alternator to generate the car’s electrical power before you need to replace it.

But what if you find that you have to replace the alternator belts every few months? Is that normal?

No, it isn’t and if it is the case, then there is quite likely an underlying problem that needs to be addressed.

So in this guide, I share some common causes why your car’s alternator belt may snap, what signs you may observe before it breaks, and lastly share some tips to help you prevent your alternator belt from breaking prematurely.

What Causes an Alternator Belt to Break

Here are 3 common reasons why an alternator belt breaks

#1. Alternator belts suffer from normal wear and tear over time. Inspect the belt periodically for signs of wear, fraying and cracks and replace with a new when you observe these signs of damage.

Make sure the alternator and drive pulleys rotate freely and are well aligned before you replace the belt.

#2. Overtightening the alternator belt increases the rate of wear and tear leading it to fail prematurely. When installing a new belt, adjust the tension following the manufacturer guidelines for setting the right alternator tension.

Note: some cars have automatic tensioning systems that make adjustment of the belt tension easy.

#3. The alternator can also break prematurely if the pulley(s) are not aligned or have damaged bearings.

Always confirm that both the alternator and drive pulleys are aligned and the belt is fitted properly before installing a new belt. This is a common cause of frequent alternator breaks.

Signs that a Car Alternator Belt has Snapped

If the car alternator belt is about to snap or has snapped, you may observe any of the following warning signs :

#1. The battery light on the car dashboard may also come one, signaling a fault with the charging system

#2. You may hear an unusual squealing sound which is may sometimes followed by smoke from under the hood.

What Happens When an Alternator Belt Breaks?

If the car alternator belt breaks then you can expect the following to happen

#1. Charging of the battery will stop. Once the battery has been drained, the car will not be able to start

#2. If you are driving, the car’s electrical system will lose power and once the car battery power has been drained and the car will stop.

This is because the alternator is the first source of power for the electrical system as you drive and in the event that it can not met the power requirements, additional power is obtained from the battery.

Without an alternator belt, the car is robbed of a source of power and therefore relies on the battery until it is drained.

You may also be interested in the post: 6 reasons why the car battery power may be drained and how to fix them

Can You Drive with A Broken Alternator Belt?

Yes, you’ll be able to start the car if the battery has enough power to start the engine but the car will eventually stop once all the battery power has been used up.

So, for as long as there is enough battery power the car engine and electricals will continue working.

How Long Can a Car Run without The Alternator Belt?

There is no one answer to this as it depends on several factors:

How Long Can You Drive With Bad Lif...
How Long Can You Drive With Bad Lifters?
  • the battery capacity (ah),
  • how much charge is left on the battery,
  • and how much power is being drawn from the battery. This in turn depends on what accessories are switched on and drawing power from the battery.

You can get the car to run longer by switching off accessories that you do not need at the time depending on your circumstances such as the sound system and others.

Tips to Prevent a Car Alternator Belt from Snapping

Herea are 3 tips to help you keep your car alternator belt working as long as possible

#1. Inspect the car alternator belt periodically for signs of wear, cracks, or stretches. The goal is to replace it before it fails.

The symptoms above can signal an impending belt failure giving you some time to replace it with another before the current one fails.

#2. Confirm that the alternator and drive pulleys are aligned before you replace the belt or when inspecting the belt condition.

Lastly, make sure to set the alternator belt tension right according to the manufacturer’s instructions.

If it is too tight, it is likely to snap prematurely. If it is loose, charging of the alternator will be intermittent and you’ll likely see the car battery light on the dashboard lighting .

Final Word

A car alternator’s belt can work reliably for many years. If your car alternator belt fails frequently, check that the alternator and drive pulleys are well aligned and that the belt tension is set right.

Lastly, remember that belt wear out with time, so from time to time inspect the belts and check for signs of wear and tear and replace it once they are observed.

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