How Hard Is It To Replace An Alternator? [Owner’s Guide]

If your car’s alternator is malfunctioning, it’s a wise idea to replace it with a working alternator. Your vehicle’s battery cannot charge properly when the alternator is faulty, which could result in your car breaking down unexpectedly. If you’re unsure of how difficult it is to replace an alternator, this is what you should know!

Replacing a vehicle’s alternator is one of the easiest automotive repairs to do at home. It will take 2 hours and cost up to $500 to replace an alternator by yourself. To replace this component, you’ll need a replacement alternator and serpentine belt, a belt tensioner tool, and basic hand tools.

If your alternator is malfunctioning, you should replace it with a working alternator as soon as possible. Luckily, it’s an easy component to replace. Once we’ve explained why this is one of the easiest automotive repairs to do yourself, we’ll break down the steps to follow when replacing your alternator!

Is Replacing An Alternator Difficult?

To prevent causing an accident or damaging your vehicle’s components due to a faulty alternator, you should replace your alternator as soon as possible. Luckily, this is one of the simplest car repairs to do at home. Depending on your knowledge of car mechanics, it will take approximately two hours to replace an alternator on your own.

If you decide to replace your vehicle’s alternator by yourself, you should expect to spend between $200 and $500 purchasing a replacement part. There are also a few tools and supplies you’ll need to replace your alternator, including basic hand tools, a belt tensioner, and a replacement serpentine belt.

If you want to save on the mechanic’s labor costs when replacing your alternator, a DIY replacement approach is a great idea. If you’ve got some automotive knowledge, the right tools, and two hours to spare, you’ll be able to replace your alternator without going to a professional mechanic. We’ll outline the simple steps to replace your alternator in the following section.

Of course, it’s also possible to hire a professional mechanic to replace your alternator. When getting a professional mechanic, you should expect to pay between $100 and $200 for labor on top of the replacement alternator’s cost.

Using a mechanic to replace your alternator is ideal for those lacking the knowledge, tools, or time it takes to make the replacement.

How to Know if Your Alternator is Gone Bad?

Generally speaking, if your car battery is not receiving any voltage, it is the alternator causing the issue.

There are multiple ways you can test an alternator at home. The most common way is what is called a bench test for an alternator. I’ve got a complete article on this topic. So, make sure you check that out.

But, generally speaking, if you notice that your battery simply dies after running your car for a few minutes or if you have to jump-start your car now and then, the problem is most likely the alternator.

The easiest way to test an alternator is by using a battery tester like this one on Amazon. Just hook the battery tester to the battery. Put the red wire on the positive terminal and the other wire on the negative terminal, and then press “Enter” on the battery tester.

You will notice that the battery tester will throw a “No Charging Voltage” error (or something on those lines are the error wording can differ from one model to another).

How To Replace Your Car’s Alternator

As we explained above, replacing your vehicle’s alternator is one of the simplest automotive repairs that can be done at home. Not only that, but it can save up to $200 on labor costs. If you want to replace your car’s alternator by yourself, you can follow these steps!

1. Gather Your Supplies

To replace your car’s alternator, you’ll need to gather the following components and tools:

2. Disconnect Your Vehicle’s Battery

To start replacing your car’s alternator, you’ll need to disconnect your battery first. Ensure your vehicle’s ignition is in the off position and disconnect the negative battery end. You’ll be able to identify the negative battery terminal with a minus sign. 

3. Disconnect The Alternator Wires

Once your battery has been disconnected, you’ll need to disconnect any wires coming from the back of your alternator. Typically, this is an easy process. You can take photos of the wires you disconnect or label them, as this will help you when reconnecting them to the new alternator.

4. Remove The Belt From The Pulley

The trickiest part of replacing an alternator is removing the drive belt from the pulley. You’ll need to locate your car’s tensioner pulley and slip the belt off the pulley. Many cars have bolt/rod-ends that can be turned with a wrench to release some tension, allowing you to remove the existing belt.

5. Loosen Bolts To Remove Alternator

When you’ve finished removing the belt from the pulley, it’s time to remove any bolts connected to your car’s alternator. Once you’ve loosened these bolts, you’ll be able to remove the alternator.

6. Compare Your Old And Replacement Alternators

Before proceeding with the alternator replacement, you should compare the removed component with the replacement one. By comparing the two alternators, you can ensure you have an appropriate replacement that will work in your vehicle.

When comparing alternators, some replacements may appear different due to consolidation. Before assuming you have the wrong replacement, consult the paperwork that came with your replacement.

7. Secure Your Replacement Alternator

You’re now ready to install the new alternator. Essentially, you’ll be reversing the steps of removing an alternator. When fitting the replacement alternator, you must ensure it fits properly and aligns with the bolt holes. You can now install the mounting bolts and nuts. You want to ensure the nuts are evenly tightened.

8. Connect Electrical Connections To Alternator

Many vehicles require that the electrical connections be installed before replacing the drive belt. However, you may need to swap Step Eight and Step Nine with some cars. When connecting the electrical wires to the alternator, you can use the photos/labels you took/made earlier.

9. Replace The Drive Belt

Don’t worry; replacing the drive belt is much easier than removing it! Once you’ve placed the drive belt in the correct position, you need to rotate the belt tensioner. Of course, you’ll need the belt tensioner tool for this. Under your car’s hood, there will also be a diagram outlining the steps to do this.

10. Reconnect Your Car’s Battery

Finally, reconnect your vehicle’s battery. You’ve now successfully replaced your vehicle’s alternator – and saved yourself at least $100 doing so!


An alternator replacement is one of the easiest automotive repairs you can perform at home. To replace an alternator on your own will take two hours and cost up to $500. To replace this component, you’ll need a replacement alternator, a drive belt, a belt tensioner, basic hand tools, and the right steps to follow!

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