What Causes An Alternator To Go Bad: 5 Must-Known Reasons

A car’s alternator plays a crucial role in its operation. It’s responsible for supplying power to the battery, making sure your vehicle runs smoothly. But what happens when things go wrong? What causes an alternator to go bad? In this article, we will dive into detailed information to help you understand this clearly.

What Causes an Alternator to Go Bad: 5 Common Causes

A few things can mess up your alternator. If you don’t start your car right or put in something that uses too much power, it can hurt your generator. If there are leaks that get into the generator or if the belt is too tight, it can damage the small parts inside, and a bad battery causes them to wear out faster. Here, we delve into these causes in greater detail to give you a clearer understanding.

Starting wrong

A common way to accidentally harm your alternator is by not starting your car correctly. And this can happen if you leave the car key turned to the “on” position before the engine is actually running.

In detail, when you turn your key to the “on” position, it completes an electrical circuit. If the car’s engine isn’t running to use and manage this electricity, the alternator ends up dealing with it. This causes too much electricity to flow into the generator, which can make it get too hot, put a strain on its parts, and could finally cause it to break down.

So, to solve this problem, it’s very simple, you just make sure to always have your car key in the “off” position when you start your car.

Starting the car

Extra gadgets

Nowadays, cars are equipped with all sorts of extra gadgets and devices. We’ve got everything from powerful sound systems and extra lights to seat heaters and fast-charge ports. All these gadgets make our car trips more comfortable and enjoyable.

But these extra gadgets can be hard on your car’s alternator. Normally, your alternator has a limit on how much power it can make. If all the electrical equipment in your car is demanding more power than the generator can produce, then it gets overloaded. Over time, this can cause the generator to wear out quicker than it should.

Thus, to solve this problem, first, you try to notice how many utilities you have running at the same time. If you don’t need it, switch it off. Also, when you want to add a new gadget to your car, think about how much extra power it will need. If your alternator can’t handle the extra power, you can think about getting a stronger one.

Leaking Fluid

Normally, alternators are located near many important parts of your car’s engine, and many of these parts need different fluids to work right. These fluids can be engine oil, coolant, and sometimes even transmission fluid. But if any of these fluids leak onto your generator, it can spell trouble.

In detail, the inside of an alternator is made to handle electricity, not liquids. When these engine fluids touch this generator, it can mess up the electricity flow, leading to what’s called a short circuit.

So, all you need to do is regular car maintenance. Keep a close eye out for any leaks of these fluids and get them fixed as soon as you spot them.

Belt tension

Another common is due to your car’s belt-driven system. If this belt is too tight, it can cause problems. Specifically, this problem will put a lot of pressure on the bearings, and the small components inside the alternator.  Moreover, it also makes these bearings wear out faster than they should, which can lead to generator failure.

So, you should ensure the alternator belt has just the right amount of tension – not too loose and not too tight. Regularly checking the condition and tension of your alternator belt can help keep your alternator working correctly and extend its lifespan.

Car’s belt


Lastly, the battery plays a key role in your car’s electrical system. It provides the power necessary to start the car and keeps all the electrical accessories running when the engine is off. The alternator’s job is to keep the battery charged while the car is running and power any electrical systems in use.

Now, if your battery is failing or faulty, it won’t hold a charge as it should. This puts extra pressure on the alternator, as it tries to compensate for the lack of power by working harder to keep the battery charged.

But your alternator isn’t built to be working flat out all the time, and over a while, this extra workload can cause it to overheat and wear out faster than it should.

So, you should regular battery checks and maintenance can help you catch any battery issues early and potentially save your alternator from premature failure. Moreover, you can clean battery terminals, ensure the battery is securely mounted, and replace it when it starts to show signs of failing.

Read more: How To Disable Steering Wheel Lock: 3 Fast Ways

Some Signs to Watch for the Generator Can Die

Firstly, the most obvious sign of a generator going bad is the “ALT” or “GEN” light on your dashboard. If this light comes on, it’s a signal that your alternator isn’t charging the battery properly.

Moreover, if your headlights or dashboard lights are dimmer than usual, this could indicate that your alternator is not supplying enough power. Next, you should also notice other electrical systems in your car starting to act up, such as the power windows, power locks, air conditioning, radio, or GPS, it might be due to a generator not supplying enough power.

Furthermore, the bearings fail which can cause a grinding noise in the engine. So, this leads to alternator failure and fixes immediate attention. In addition, if your engine is misfiring or having trouble starting, it could be because your spark plugs aren’t getting enough power from the generator. Lastly, when you notice your battery is constantly dying or losing its charge, this might be a sign of a generator issue.

Car Alternator

How To Prevent Alternator Failure

Keeping your car’s generator in good condition can help you avoid unexpected issues in the future. Here are some tips you can follow:

  • Regular checks: Keep an eye on your alternator for any signs of damage. If the belt or wiring looks worn, get it fixed right away. Having your car serviced regularly should also include a generator check.
  • Battery care: Look after your battery to help your generator last longer. Make sure the battery is in good shape and replace it as soon as it starts to wear out.
  • Avoid overloading: Don’t run too many gadgets that use a lot of power all at once for a long time. This can overwork your generator.
  • Check for leaks: Make sure no engine fluid is dripping onto the alternator. This can cause a short circuit and make this generator fail.
  • Belt tension: The belt on the alternator should not be too tight. If it is, it could damage the generator’s bearings and make it fail.
  • Clean regularly: Dust and other small particles can affect how well the alternator works. Regular cleaning of your generator and its surroundings can help it last longer.

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Understanding what causes a generator to go bad and recognizing the signs of failure can save you from unexpected car trouble. Regular maintenance and prompt attention to issues can help keep your alternator and car running smoothly.


  1. What can make an alternator go bad faster?

    Age and regular use can make an alternator go bad quickly. If engine oil or power steering fluid leaks on it, this can cause it to stop working too. Also, if you're using a lot of electrical things in your car while idling for a long time, it can wear out the alternator.

  2. What is the usual problem with alternators?

    The most common issue with alternators is when the small bearings inside them break. These bearings let the inside part of the alternator spin freely, but they can break down over time from heat and dirt.

  3. Do I need to change the battery when I put in a new alternator?

    When you put a new alternator in your car, you should also check your battery. Most guides for installing a new alternator say that you need to unplug the battery before you put the new one in.

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