Alternator Repair And Cost [Sept. 2022 Guide] - Auto Chimps

Picture this: it’s early morning, you’ve finished getting ready for work and are headed out to your car.

As you put the key in the ignition and turn it, it doesn’t seem to want to begin.

Should you call the office to let them know you might be arriving delayed?

You decide to try one more time, and fortunately, after a few seconds, it cranks over.

The weather is a bit cold, so you decide to turn on the heater, when all of a sudden, your lights flicker and dim. OK, that’s strange!

As you navigate your way out of the driveway, you notice a minor whining noise coming from behind the dash. Then, out of nowhere, the battery indicator light appears.

It sounds like you might have a problem with your alternator. If you didn’t know, an alternator is in charge of supplying your car with power. It ensures things like your heater, power steering, and lights have sufficient juice to function.

How much does an alternator replacement cost?

It depends if a repair is feasible. If not, you’ll have to have it replaced, which can run between $500 to $1,000 (including parts and labor). Otherwise, for something simple like replacing an alternator belt, expect to pay about $100-$150 (not including assessment).

Fortunately, in this exhaustive guide, we will cover this in more detail. We will start by reviewing how an alternator works.

Then, we will examine a few of the most frequent symptoms that suggest there might be an issue with it, as well as how to test it yourself at home. Lastly, we’ll go over the exact costs associated with alternator repairs.

Let’s get the fundamentals down first.

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How An Alternator Works

Simply put, an alternator transforms mechanical energy, which is produced by your engine, into electric power.

Parts such as your air conditioning, steering, windows, and radio cannot operate using mechanical energy. Instead, they require electricity, making the alternator vital.

You might think your battery handles this, but in reality, it’s only responsible for getting your car started in the first place. This means that the battery starts the engine, and the alternator keeps it operating.

The main components of an alternator include the following:

Rotor And Stator

The rotor and stator work via a belt connected to your crankshaft. As the crankshaft rotates, it causes the rotor to whirl within the stator. This creates a magnetic field that results in an electrical current being generated.

Diode/Rectifier Assembly

The diode assembly receives that electricity and converts it from AC (alternating current) to DC (direct current). This is then directed outwards to power the various components of your vehicle.

Voltage Regulator

You can think of the voltage regulator as essentially a surge protector for the alternator, controlling the amount of power it generates. If there’s too much electricity being sent, it can damage the various components. Yet, if there’s insufficient electricity, they won’t be able to function.

If any of these elements has an issue, it will compromise the ability of your alternator to continue operating.

This means your car will have problems starting due to a battery not being charged. Not only that, but your electronic components won’t receive the power they need to function.

Now that you understand the fundamentals behind how an alternator does what it does. Let’s examine a few indicators that suggest it’s having difficulties.

Symptoms Of A Faulty Alternator

Your Car Has Trouble Starting

As we mentioned earlier, the battery is responsible for starting the engine in the first place, and the alternator keeps it functional.

However, the alternator also replenishes the battery, preventing it from becoming depleted.

If you notice a clicking sound after turning the key, you need to determine which is defective. Thankfully, we’ll discuss how to do so in the following section.

Issues With Electrical Components

Remember, the alternator has a vital job; it powers all of the electrical components in your vehicle.

For this reason, if there’s an issue with it, it won’t be able to continue doing so.

Watch for indications that suggest it’s having difficulty to keep up.

Some of these include your power windows rolling up or down more slowly than usual or weak or flickering headlights or dash lights.

If you detect an issue with your alternator early on, it’s essential to fix it promptly to prevent a total shutdown.

Whining Or Growling Sounds

As stated previously, your alternator runs off a belt that’s connected to the crankshaft. If you notice a sharp or growling sound coming from under the hood, it signals there might be an issue with the system. These include damaged or misaligned belts or deteriorated bearings.

Indicator Light Comes On

One of the most apparent signs of an issue with your charging system is if an indicator light in the form of a battery illuminates.

While it doesn’t necessarily suggest the alternator, it does indicate it.

The first step when this happens is to determine where the issue is coming from, whether it’s the battery or alternator.

Speaking of diagnosing the cause. Let’s look at how to examine both your alternator and battery for issues. This is essential to know since replacing a battery carries significantly less of a cost than alternator repairs.

How To Test If An Alternator Is Working Correctly

For either of these tests, you’ll first need to have a multimeter, which is used to measure the voltage, current, and resistance. These can run for anywhere between $15 for a simple multimeter and as much as $100 for one with more sophisticated features.

For this test, a basic-level unit will suffice just perfectly.

Test The Battery

A multimeter will have two probes, a red one, and a dark.

Start by connecting the red side to the positive battery terminal and the black to the negative terminal (they will be marked by a plus or minus sign).

12.6V is the crucial number, which should not drop far below this range.

Anything below 12.2 means your battery is only partially charged. If it is substantially above, then there is a problem that may lead to a blown alternator or battery.

If it is low, unhook the battery from the car and attach it to a charger. Once finished, disconnect it from the charger and let it sit overnight. Test it again in the morning, and if it’s still inadequate, you’ve got yourself a defective battery.

Test The Alternator

First, start your engine since this is when the alternator is functioning. Next, connect the multimeter probes to your battery, similar to the previous test.

You should get a measurement of between 13.8V to 14.4V.

Anything outside this range means your alternator is not functioning properly. In this case, you will need to either repair or replace it.

Now that you know how to determine where the issue is originating. Let’s get down to the costs of an alternator repair or replacement.

Alternator Repair Costs

The average hourly rate runs between $50 at a small garage to about $100 at a typical dealership.

Then there’s the diagnostic fee of about $80-$120, though some may charge a little more.

Your choices include getting a fresh alternator or a refurbished or used one. Clearly, a new alternator will cost the most, but it is guaranteed to last the longest.

Fortunately, either a fresh one or a reconditioned one should come with a warranty.

Pre-owned alternators have heightened risk and, realistically, may either already have a problem or fail at any moment.

The cost of the three options typically ranges from about $300 to $500. The replacement itself should only take about 2 hours. Add this all together, and you have a total cost for an alternator replacement of between $500 to $950.

Regarding repairs, sometimes all that’s needed is a fresh belt or to clean connecting points.

In this case, you still pay the diagnostic fee and hourly rate, which should total a few hundred dollars, depending on the make and type of your car.

Final Thoughts

You should now have everything you need to determine whether you need an alternator repair or substitution.

The last thing you want is to spend a considerable sum on a new one when the issue is something else, like a defective battery.

Additionally, knowing the typical cost range ensures you don’t get overcharged at a shop.

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