Replacing An Alternator: Here's How Long It Takes

Replacing An Alternator: Here’s How Long It Takes

Your car’s alternator is essential for it to function correctly and provide you with safe transportation. In some instances, this critical car part gives out, often during times when you can least afford it.

No one wants to hear their mechanic tell them they need a new alternator. Many people dread replacing this essential part of their car because it can be costly. 

The hassles of not knowing how long replacing the part can take and how much it will cost can be stressful.

Are you wondering how long Replacing an alternator takes? Many factors can play into the time your car is out of commission, but it generally takes two hours for your alternator to be professionally replaced. If you choose to go the DIY route, the job can take up to 5 hours to complete.

If you need a new alternator, here are the steps involved in alternator replacement and some other contributing factors to take note of as you try to get back on the road.

Table of Contents

Signs That It’s Time to Replace Your Alternator

Your alternator is responsible for helping your car’s battery keep its charge and providing power to your vehicle’s electrical systems. Without a functioning alternator, your car battery can quickly drain, causing the engine to stall out and compromising your car’s electrical systems.

You’ll know your alternator is in trouble if you’ve noticed these symptoms and a few others like

  • Flickering lights
  • Strange grinding sounds
  • Poor battery function
  • Difficulty getting the car to start

If you’ve noticed these signs while driving, getting to your mechanic right away is crucial because your battery may only last a few more minutes before giving out, creating even more headaches.

Disconnect the Battery

The first step in alternator replacement is disconnecting the battery from its charging source. Although both the battery and alternator may be drained at this point, disconnecting the battery ensures you won’t accidentally shock yourself by grounding a live wire.

Remove the Wires

 After removing the battery, it’s time to disconnect the wires. Depending on the experience level of the mechanic performing the alternator replacement, this step has the most potential to run into trouble. 

As you remove the wires, make note of their arrangement as it’s easy to get them mixed up—spelling bad news for your repairs.

Remove the Serpentine Belt

Once the wires are gone, the serpentine belt that powers the alternator must be removed from the car next. Like disconnecting the wires, it’s crucial to exercise extreme caution with this step. The tension on the belt can make it challenging to remove from the pulley holding it in place. 

While you may be tempted to force it out, don’t do it as you could damage or snap the belt and create serious issues.

Some of the tools needed for removing the Serpentine Belt may include

  • A torque wrench
  • A Belt tensioner tool (if necessary)
  • Socket wrench
  • A Serpentine Belt tool (if necessary)

Removing the Alternator

Taking out the serpentine belt is often the most challenging part of alternator replacement and can set even the best mechanic back for a while. When you’ve removed the serpentine belt it’s time to take the alternator out, which you can do after the surrounding bolts are removed.

Put in Your New Alternator

Once you’ve removed the faulty alternator, it’s time to replace it with the new one. But, remember to re-install the serpentine belt you removed earlier (or install a new one if needed)

Contributing Factors For Alternator Replacement


One of the critical factors in getting your alternator replaced is if the part is readily available for purchase. Auto shops sometimes don’t have vehicle parts you need ready for immediate use. If the part isn’t in stock, it means the store will have to order your alternator from their distributor, which can take a few days, or a few weeks in certain circumstances.

Vehicle Make and Model

Another factor that contributes to your alternator’s replacement is the make and model of your vehicle. Many car manufacturers have certain design specifications for the parts of their vehicles, and not all alternator designs can fit their models. These differences can make it tricky to find the right part quickly.

Also, the make and model of your car is important because depending on your car’s model year, it can be complicated to find exact matches of replacement alternators for older cars.  

Mechanic Skill

The job of replacing an alternator is no easy feat for novices, and many experts recommend that you have the work done by a professional as opposed to taking on the job yourself. That said, the skill level of the mechanic involved can affect how long it takes to install your new alternator.

For instance, seasoned mechanics are experienced in intricate jobs like alternator replacement, but newer mechanics may need extra time to ensure the job is done correctly. 

You should carefully search for a reputable mechanic to complete the job. While it may be tempting, choosing the cheapest option may not produce the best work. If your mechanic doesn’t install the alternator properly, it can open the door to several other car problems, adding to your frustration and draining your wallet. 

Having an experienced professional complete the job can make the difference in getting back on the road sooner than later.

Wait Times

Depending on how busy your mechanic is, installing your alternator may not be a simple in-and-out process. 

Sometimes, even seasoned mechanics get behind and have to catch up on the needs of other customers, leaving you waiting longer to get your alternator installed.


Needing to replace an alternator can be stressful and expensive, but understanding the steps involved can help you get back on the road in a reasonable timeframe. There are some factors out of your control that may delay the process. 

But, if you know how to handle the job on your own, or have a reliable mechanic, you can be back on the road in a few hours if all goes according to plan.

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