How Long Does It Take to Replace an Alternator?

Do you have issues with your car alternator and don’t know how to go about it? Do you want to replace your car alternator with a new one and are wondering, how long does it take to replace an alternator?

Look no further because you have found the right place. We will give you all the information you need about alternator replacement, how long it will take, how much it costs, and so much more.

Let’s begin!

Trying to replace an alternator yourself is possible, but you must be familiar with mechanical tools and how it works; better, you will need mechanical experience; otherwise, you may damage more components and worsen your car’s condition.

Doing it yourself won’t take more than five hours, but please be sure you have experience in such a job. If not, please get a good mechanic to do it.

Related: Alternator Repair Options And Which You Should Choose

What Is an Alternator & What Does It Do?

How Long Does It Take To Replace an Alternator

Your car battery is responsible for generating the needed electrical power to kick start the ignition.

When the ignition has turned on, the car battery will serve as electrical storage, used in times of alternator problems. Ideally, the alternator is the powerhouse and power supply of your car.

The alternator produces electrical energy by converting the mechanical energy in the internal combustion engine.

This electrical energy provides power for all your car electronics and electrical components.

The rotational force of the engine achieves the conversion of mechanical energy into electrical energy by the alternator.

Just like an electrical motor, the alternator works in reverse. So picturing an alternator as an electrical motor operating in reverse will help you better understand how it works.

Your vehicle’s starter provides the electricity necessary to start your vehicle using the car battery since that is its sole purpose.

The alternator then comes in after the ignition is turned on and provide electricity for all the car’s electronic and electrical system. It also charges the battery while the car is running, preventing the battery from running down.

Signs of a Bad Alternator

One of the primary purposes of an alternator is to ensure that your car’s battery does not run down by keeping it charged at all times, even as you drive.

When you start having power issues, your car alternator could be bad. You will observe that your dashboard light and other interior lights become dimmer when the alternator gets bad.

When you confirm the alternator is the problem, replacing it is the best option because failure to do so can get you stranded on the road.

The battery always comes to mind whenever a car driver thinks of his car’s electrical power; meanwhile, the battery does not produce much of the power used by the vehicle.

The alternator is the primary electronic and electrical power source for a car. Therefore whenever it gets faulty, it poses a severe threat to the car’s functionality. Here are some common signs when your car alternator gets bad.

  1. Your car will find it challenging to start; at some point, it won’t start no matter how hard you try unless the alternator is replaced with a new one or fixed.
  2. Your car engine will be stalling.
  3. Your car’s electrical and electronic components will start developing issues.
  4. You will start hearing unpleasing noises coming out of your car.

Check out or our article on 10 Signs Of A Bad Alternator for more detailed information on the signs of a bad alternator

How Long Does an Alternator Last?

The lifespan of an alternator depends mainly on how frequently the car is used and how careful it is used.

Unlike batteries, alternators last longer; they can last as much as 4 to 7 years. Alternators can cover up to 80k miles before they start giving signs for replacement.

However, some cars will start showing symptoms at 40k miles or thereabout. As for brand new cars, they won’t have alternator problems till they have covered 40k-80k miles.

How to Replace an Alternator

How Long Does It Take To Replace an Alternator

Replacing an alternator comes with some tasks that will require some special tools. Some of these tools needed for proper replacement of an alternator are:

  • Voltmeter for checking out the voltage
  • opened wrenches
  • large screwdriver
  • socket wrenches for easily disconnection or fastening of the replacement part (i.e., the new alternator),
  • memory saver and safety working gloves.

The alternator cost can be a big deal; it can be pretty expensive depending on your car’s make and model.

The belt tension alone will cost around $50-$100, while it can cost as much as $1,000 for this replacement when you take it to a mechanic.

You will be required to have a good level of mechanical skill before you carry out this task, and it will take you about an hour to successfully change the belt.

You will need to be careful when removing the belt and putting on the new one. Make a proper assessment before you carry out the replacement.

Step 1: Inspect the Parts

Testing the batteries should be your starting point; this is to confirm that the battery is healthy enough or will need to be changed.

If the battery is good, your voltmeter should be reading about 12.5 volts when the car is off, and if started, it will be reading about 14 volts.

If the alternator spikes or stays the same, there’s a problem, and it should be replaced. Also, the battery should be 100 percent charged.

However, it should not be 50 percent charged when starting the repair; else, you may run into trouble.

Please save the preset using a memory saver; this will help to retain the preset while you repair it.

Examine your car belt before you begin wrenching; this will save you many troubles. New cars come with a serpentine belt, while older ones come with a V belt. Verify to be sure there’s no wear and cracks.

If there are signs of wear or crack, please buy one while buying the alternator; this will save you the stress and cost of returning the belt.

Check out the battery and see if there’s corrosion within it; clean and polish them out if there are any. You can also buy anti-corrosion products to help prevent subsequent corrosion.

Finally, investigate the cables to be sure of no signs of wear. If the rubber casing has dried out, you can get a new one and replace it, and it won’t cost more than $20.

Step 2: Disconnect the Battery’s Power

Disconnecting the battery power is the next step. Holding a metal tool while working with a live electric current can be very dangerous.

It could lead to more damage and be a threat to your life. In addition, it can increase the cost by damaging components which will force you to buy a replacement.

Therefore disconnect by removing the negative cable; you don’t necessarily need to remove the positive cable. Just one is enough to keep you safe by breaking off the current.

Step 3: Take off the Alternator

When you are done with successfully disconnecting the battery, move to the alternator and do the same, disconnect the power cable of the alternator with either an open-ended wrench or a socket.

Also, detach the harness; then, losing the belt is next. Remember losing the belt is dependent on the type of car you are using.

Some vehicles will require unscrewing the hardware holding the belt, while for some, the use of belt tensioner tools will be enough. You will need to remove the belt if there is damage.

Removing a serpentine belt requires a great deal of carefulness; tension force can be very harmful, don’t allow it to hit you or any sensitive part of the car; as soon as you are done losing it, carry on your repair.

When the above steps have been completed, remove the faulty alternator, place your hands on the housing, and quietly remove it.

When it is out, compare the old and new to ascertain that you got the right alternator. Confirm the location connection and the alignment of the holes.

If they don’t look the same, you have to take the newly purchased alternator back to the seller and ask for the suitable one.

Step 4: Replacing the Old Alternator With the New Alternator

When you compare and confirm that the new alternator is suitable, place the new alternator into the housing. Be careful so that you don’t pinch any wire. Be gentle with it, don’t add too much force.

Next, install the new belt; if you plan on doing that, else fasten the bolt and ensure it is tight enough. If you can’t get a pulley, use a pry bar instead.

Finding a Goldilocks spot is golden and ideal, a spot that is not too loose or too tight. This sweet spot should be around a one-half inch of play.

When you are done with that, take the cable and harness of the newly installed alternator. Then, follow the reverse steps you took when taking off the old alternator.

Pay attention to the tension of the belt when you are done, and ensure that nothing is left inside the engine; make sure that the bolt is well tightened.

Step 5: Reconnect the Battery and Test the New Alternator

Suppose you have come this far, congratulations. However, you will need to confirm if all you have done is correct and now is the time.

Connect back the negative cable to the battery. Ensure that the positive and the reconnected negative cable are tight. Switch on the vehicle are observe the voltmeter reading.

Your voltmeter reading should be around 13.5 volts when nothing is running in the car.

If the volt reading is too high or too low, something was not done correctly. Else if it maintains that 13.5 volts, then you are mechanically correct.

After you have driven your car for a few days, check out the tension and make sure everything is in order the way it should be.

If everything looks great, then a huge congratulations on a job well done. Remember to preset your car using the memory saver; the instructions in the device will guide you on how to do that successfully.

Check out this video for more tips on how to replace an alternator

Frequently Asked Questions – How Long Does It Take To Replace an Alternator?

Is It Hard to Change an Alternator?

Replacing an alternator is not that difficult. You only need the right tool with good experience or mechanical skill to successfully carry out the replacement yourself.

How Much Does It Cost to Replace an Alternator?

Changing an alternator is quite expensive. It ranges from $500 to $1000, depending on your car’s make and model. In some vehicles, the alternator cost can be way more.

Is Replacing an Alternator a Big Job?

Replacing an alternator is quite a sensitive procedure that requires an excellent level of carefulness because if the belt is not handled correctly, it can create another problem. Generally, it is not a big job, but it is best handled by an expert or a professional mechanic.

How Long Can You Drive With a Failing Alternator?

If you are lucky, you can get 30min drive time when your car alternator gets bad. But unfortunately, most cars will only get just 25 minutes of drive time because the battery will quickly go empty since nothing is charging it.

Do Alternators Fail Suddenly?

Yes, your car alternator can fail suddenly. However, most times, it shows signs of failure, and slowly the problem causing the failure will get worse, and drivers do not always pay attention to these signs until they get disappointed by the alternator.

What Happens if the Alternator Dies While Driving?

If while driving and your car’s alternator fails, the car battery will stop charging; within minutes, the battery will run down, and the car will stop working. The sole duty of the alternator is not to make sure your car battery is charging consistently so long as it is not a dead battery.

Can You Start a Car With a Dead Alternator?

The solution to this question is jumpstarting the car; a dead alternator won’t help start a vehicle; when you jumpstart your vehicle with a secondary vehicle, that is only when your car will start. Note that your vehicle will only run for a few minutes after jumpstarting, so make good use of your time.

Why Does My Car Keep Dying With a New Battery and Alternator?

The cause of this problem could be corrosion. If the battery connection is corroded, it will create difficulty in charging the battery resulting in the battery dying quickly and the alternator not being able to do its job.

Conclusion – How Long Does It Take To Replace an Alternator?

This article has answered your question: How Long Does It Take to Replace an Alternator? It has also explained what an alternator is, the signs of a faulty alternator, and how to replace it.

It will take a professional mechanic about two hours to replace an alternator, although factors like car make and model can influence this time. Timing may also vary depending on the mechanic’s knowledge, and some automobile shops in the United States see the job as a complete workday job, and they charge as such.

We have also stressed that it is not advisable to carry out the replacement yourself if you don’t have prior knowledge of doing it or mechanical skills.

However, the steps we have explained above will guide you if you are to do it yourself.

Scott Greene is a seasoned automotive technician for over 5 years and has been deep into advanced automotive diagnostics for a couple of years. He Loves writing about Automotive Diagnostics and Repair, Trouble codes, Buyer guides for various car parts and accessories, and lots more. 

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