Updated at: 14-08-2022 - By: Lucas

In terms of a vehicle’s ability to run on electricity, drivers tend to focus most of their attention on the battery. The car’s battery, on the other hand, generates the least amount of power. It is the alternator that powers all of your car’s major accessories and electrical components.

What an alternator does, how long does it take to replace an alternator, and how can you tell if it’s not operating properly are some of the questions we’ll answer here.

What Is an Alternator & What Does It Do?

How Long Does It Take To Replace An Alternator-1

In order to start your car, the battery creates the necessary electrical charge. As a result, your battery is now only useful in the event of an alternator failure. The alternator is generally referred to as the “monarch” of a car’s power supply because of its importance.

The power supply. The part of an internal combustion engine that converts mechanical energy into electrical energy is known as the generator. The alternator generates the electricity that powers the vehicle’s electronics.

The alternator is a generator that utilizes the engine’s rotating motion to convert mechanical energy into electrical energy. If you conceive of the system as a reversed electric motor, you’ll have no trouble grasping its workings.

The only power your battery supplies is for the electronic starter, which is all you need to get your car started. Your alternator begins generating power for all of your vehicle’s systems whenever the ignition is turned on. It also keeps the battery from getting depleted by charging it continuously while the car is moving.

How Long Does It Take to Change an Alternator?

Depending on the model and year of your car, an alternator replacement should take a competent mechanic no more than two hours. A full day’s work is usually charged in most US shops.

Even if you have no prior knowledge of auto repair, it should take you anywhere from 3 to 4 hours to perform the replacement yourself at home. Replace your alternator with the help of an expert only if you are confident in your mechanical abilities. Electrical work has the potential to do harm to both you and your vehicle.

How Long Does an Alternator Last?

In comparison to automotive batteries, alternators have a far longer service life. However, when asked about the lifespan of an alternator, automakers prefer to give varying replies. Depending on how often you use your automobile, you should anticipate the alternator to last anywhere from four to seven years on average.

A car’s alternator typically has to be replaced after 40 to 80 thousand miles of use. When it comes to a new car, it’s unlikely to have any issues until it hits the 80K-mile mark.

How to Know If Your Alternator is Bad?

How Long Does It Take To Replace An Alternator-3

Your car’s electrical system would not function without the alternator, a small but crucial part. It’s possible that if it quits working, the vehicle’s electrical accessories will cease working as well, rendering it utterly useless.

Dimming/Flickering Lights

Flickering lights on the instrument panel are a warning sign that your vehicle’s alternator may be failing. Another telltale indicator of an underperforming alternator is dimming and flickering headlights while your car is idling.

Additionally, the radio or climate controls may not function as expected. Any issue with your car’s electronics could be an indication that your alternator is bad.

Grinding Sounds

A rotor inside your car’s alternator spins to provide an alternately steady and fluctuating stream of electricity. Increasing friction in the alternator can occur if the alternator is not properly oiled, fractured, or otherwise damaged. As a result, it will be forced to work significantly more to produce electricity than before. In addition, you may hear grinding noises during the procedure because of the fractured surface.

Sliding Belt / Bad Pulleys

The engine’s power is fed into the alternator’s rotor by means of a belt. A belt is also turned by the motor’s rotation. Other than the alternator, this belt runs the steering hydraulic pump and the air conditioning in most vehicles.

The alternator’s pulley or belt may possibly be the source of a malfunction. However, belt and pulley issues might arise for a variety of different causes. Any garage you take your automobile to will do a more complete analysis of all the belt attachments inside the hood in order to locate the problem.

Shutting Off While Driving

Your car’s lights and accessories will go off on their own if the alternator fails, and the vehicle will stop working while you’re driving.

The battery will deplete to the point of no return if the alternator is not functioning properly. Then, the vehicle goes out of service. In order for the starter motor to start, the battery needs to be charged. Instead, you’ll have to come up with a fast charging strategy. Find out what to do if something happens to you in our FAQ section below.

Battery Warning Light

If there is an issue with charging your vehicle’s battery, a red battery warning light will appear on your vehicle’s instrument panel. Due to the nature of the light, you can mistakenly believe that the stimulus indicates an issue with your car battery, but this actually indicates a problem with your alternator.

The battery and alternator are linked directly. In order to start your car, you’ll just need a small amount of battery power. The alternator keeps the battery and the engine charged. ” A faulty alternator could be to blame for any battery issues you’re having with your car.

How to Replace Your Alternator?

How Long Does It Take To Replace An Alternator

Repairing your alternator involves working with electricity, which can be hazardous if you don’t have the proper training and equipment. If this is the case, seek the advice of an expert. If you want to do it correctly the first time, you won’t need much expertise working on cars to accomplish this task.

It’s also a good idea to check your car’s owner’s manual for specific instructions, as this repair can vary greatly depending on your vehicle’s make and model.

ChrisFix’s YouTube video is a great resource if you need a visual explanation:

Tools Needed

For this repair, you’ll need a few simple tools. It’s ideal if you have them all ready to go before you begin. This is everything you’ll need to replace an alternator with:

As of the date/time specified, prices and availability are subject to change. A customer who purchases this item will be subject to the price and availability information that is displayed at the time of purchase on [the relevant Amazon site(s), as applicable].

For your exact make and model, you’ll need replacement parts such as an alternator, battery, belts and tensioners, bolts and cables.


The first step is to remove the battery line from the positive terminal and locate the alternator in your engine compartment. You should park your automobile on a level place and jack it up in order to reach it from the top if it is lower than the ground. If you’re going to lift your vehicle, make sure you have the handbrake on and that it’s on jack stands. A jack isn’t strong enough to hold you down while you’re under the car. It’s not going to go well.

Remove Your Alternator

Using a socket wrench, move the alternator pulley to release the belt. To remove the alternator, remove the nuts that hold it in place. Between two and four minutes will elapse depending on the model of your bolt and the method you used to remove it.

While the alternator is in position, use a socket wrench or a ratchet to remove the bolts. Unscrew and unhook the alternator’s mounting bolts, then remove it. Between two and four minutes should elapse depending on the model of bolts you have.

Install Your New Alternator

Compare the new alternator to the old one to make sure it’s working properly. Regulator and pulley voltage must match that of the old one. If the alternator doesn’t fit, return it to the store where you bought it and get a new one.

In order to install the new alternator, you must reverse the order of the old one. Connect the new alternator’s electrical connectors and wires, slide it into place, and begin tightening the bolts. Alternatively: While the bolts are being installed, the alternator pulley should be replaced, and the timing belt should be properly adjusted. Put the belt on top of the alternator pulley with the help of a socket wrench. Release the pulley to keep the belt under tension.

The positive battery cable must be reconnected. Start your vehicle and check to see if the alternator is charging your battery.

How Much Does It Cost to Replace an Alternator?

Your car’s manufacture and model play a big role in the price. They range in price from $100 to $400. You’ll pay extra if you get your parts from the dealership. About $120 to $200 in labor costs should be expected. As a result, you should expect to pay anywhere from $350 to $1000, depending on the model and year of your vehicle.


What should I do if my alternator stops working?

As soon as possible, you should try driving to your mechanic and getting the problem fixed there. If your alternator fails, you’ll have to rely only on your battery to power your automobile, and it won’t last long. Also, if you shut off your engine, you may not be able to restart it and may need a tow.

What should I do if my alternator is good but my battery gets drained?

Batteries deplete over time if you leave a car parked for an extended period of time. If this is the case, your vehicle’s starter motor will be unable to function properly. Approximately 20 minutes at 40 mph should enough if you are able to jump or push start your vehicle. If your alternator is unable to charge your battery, you may need to replace your battery.

Where should I get a new alternator?

You can look for vehicle parts in your neighborhood and on the internet. Don’t buy anything until you know the specific part number or have the alternator in your hands.

If my battery warning light turns on, do I need a new alternator?

The battery light in your automobile can come on for a variety of reasons while you’re driving. A malfunctioning alternator or corroded battery connections or slack cables are two possibilities. Prior to purchasing any parts, be careful to identify the problem.

How Do I Test My Car’s Battery?

To examine the health of your battery, you’ll need a voltmeter. To begin, turn off the ignition and all of the lights in the vehicle. The red or positive voltmeter wire should be connected to the positive terminal of your battery, and the black or negative voltmeter wire should be connected to the negative terminal. You need to charge your battery if its voltage is less than 12. 45 volts (75 percent).


Once you’ve replaced an alternator a few times, it should take you about two hours to do so again. Don’t forget to check your car’s manual before beginning the operation, and be careful when working with electricity. When replacing an alternator, only utilize OEM quality or original parts.