If you’re constantly having to charge the battery, the electronics don’t run when you’re driving the vehicle, or you have other power supply issues while driving, the alternator is a likely culprit.
These electric generators convert mechanical energy from the engine into electrical energy, keeping your vehicle running without relying on the battery. When they start to go out, the only fix is usually to replace them.
The average cost of replacing an alternator is $500-$1500. Here, the largest cost factor is your make and model of vehicle, because alternators cost anywhere from $100-$2,500. However, on average, you’re looking at around $800 in parts and labor.
The table below shows a quick price comparison of alternator replacement cost estimates from reputable suppliers:
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Alternator Replacement Cost Estimates*
Alternators can vary in cost based on vehicle make and model and performance. In some cases, you can also opt for a remanufactured alternator instead.
In addition, you’ll have to consider if you have to replace alternator belts or other parts. Finally, the mechanic’s rate, usually 1-4 hours or an average of 2, will have a large impact on the cost of replacing your alternator.
However, because the make and model of your vehicle are the largest cost factor, the following chart shows cost estimates for 10 popular vehicle make and models.
|Range Rover Velar
*Note: Prices are estimates and were correct at the time of writing (March 2022). Cost estimates may have changed since, our figures should be used as a starting point for your own research.
Alternator Replacement Price Factors
In most cases, the largest factor in replacing an alternator is the make and model of the vehicle.
However, you’ll also have to consider if your alternator really needs to be replaced rather than just repaired, the cost of the mechanic, and any other parts that have to be replaced at the same time.
Make and Model
The make and model of your alternator are the two most important factors affecting cost. Here, you’ll likely want to check estimates for your specific vehicle.
In most cases, the cost of the alternator will vary because brands use different types of alternators, different grades of alternators, and charge different amounts for parts.
For example, if you buy an Original Equipment Manufacture alternator, it’s always going to be more expensive than a made to fit alternative.
Similarly, if you have the work done at a dealer, it almost always costs more than having it done at a mechanic’s shop.
In addition, the cost of an alternator replacement depends on the make and model because engines use different setups. In most vehicles, you can fairly quickly remove the alternator and put a new one in.
You can expect the full job to take 1-2 hours for most cars. However, in some cases, you’ll have to remove more of the engine, with the longest jobs taking up to 4 hours.
Mechanic’s Hourly Rate
The second largest price factor in replacing an alternator is what your mechanic charges.
If you’re looking at an hour of work, you probably have to pay an hour of work plus the shop fee. In some cases, the mechanic will have a minimum number of hours to work.
Nationally, mechanic’s rates range between $15 and $205+. That means your actual rate will vary significantly.
If you go to a chain like PepBoys you can normally expect that rate to be $99+. In some cases, you’ll also get a flat rate.
However, if you do have a complicated teardown to remove the old part, you’re looking at the labor being the largest aspect of cost.
Other Replacement Parts
In some cases, it’s easy enough to just replace the alternator. In other cases, you’ll also have to replace the alternator belt. That will cost you an additional $100-$200 in most cases.
Alternators usually last about 70,000+ miles, or an average of 5-8 years. If your alternator has gone out sooner, you’ll also want to inspect the engine to see what could have caused the extra wear.
Condition of the Alternator
You can always save money by choosing a remanufactured or rebuilt alternator. In this case, you’re paying for a part that has been taken out and repaired to meet original manufacturer’s specifications.
Some mechanics work with these and others do not. But, if you’re using a higher-end part, going for remanufactured can save you more than half the money.
On the other hand, if your vehicle is very new, you probably want a new alternator to ensure that it lasts as long as possible.
5 Signs of a Bad Alternator
If your alternator is going out, chances are, you’ll think it’s a battery issue first. Normally, you’ll notice problems with the electronics and the lights, or even that your battery keeps going dead.
However, there are a few very easy ways to make sure it’s your alternator and not the battery itself.
1. Inconsistent Lighting While Driving
The alternator turns mechanical energy into electric energy which is used to power the lights and other electronics in your vehicle. So, when it starts to fail, it normally provides inconsistent voltage.
This can mean spikes or drops in the power supplied. The easiest way to notice this is if your lights including headlights and cabin lights spike and dim.
So, if you’re driving and the lights flare or suddenly dim and then go back up, it’s usually a good sign of inconsistent power.
Does it specifically mean a bad alternator? No. You could have cabling issues as well.
For example, if your lights are loose, they could show the same pattern of flaring and dimming. But, if the cables are all in place and there’s no damage, chances are, it is the alternator.
You’ll also not see this kind of flaring when parked and with the engine off, because it should only happen when pulling current from the alternator rather than the battery.
2. Battery Not Charging
Another very noticeable sign of a bad alternator is that your battery keeps going dead. Here, you might have a battery problem as well.
However, you can easily check this with a multimeter and a few minutes of your time. If you don’t own a multimeter, take it to an Autoparts shop and they will often test it for free or for a few dollars.
Alternators charge the battery during driving. If they don’t, the battery goes dead when you’re running the electronics.
You might park and then be unable to restart your vehicle. Or, you might struggle to start and then have dim lights or your electronics stop working.
So, when is it a bad battery and when is it a charging issue? You’ll want to take your battery out and test it.
Use a multimeter on the battery, attaching the clips to the negative and positive poles, and then check your readout. If it’s around 12.4 or higher, the battery is still good. You can charge it.
If it goes dead again, the alternator isn’t functioning properly or you’re draining power in some other way.
In addition, you can check the battery before turning the engine on. Check the readout on the multimeter and write it down. Then, turn the engine on and allow it to idle for 3-5 minutes.
Check your battery. If your alternator is working properly, it should read between 13.7 and 14.7. And, if your battery reads that when the engine is off, you have a different problem entirely.
If your battery light comes on while driving, it’s also usually a sign the alternator isn’t working.
3. Slow Electronics
If your car’s electronics aren’t working properly, it might be because of the alternator. Here, the vehicle diverts power based on priority.
So, if your alternator isn’t putting out enough current, you might have enough to run the headlights and the power steering.
However, you might start to notice issues with things like the electric windows, the radio, or even the air conditioning. If you notice your windows are very slow or your radio keeps shutting off, it’s probably a power issue.
You can test this by turning everything on. If your alternator is the issue, you’d normally expect it to fail or those electronics to stop working.
4. Difficulty Starting
Your ignition relies on a significant amount of power from the battery to start. This means that if your alternator is failing, you’ll have more and more difficulty starting the engine.
In addition, most engines use electronics to stay running. If you cut power or don’t have enough power, you’ll start to notice stalling. Both of these issues are about power supply.
However, they can stem from nearly any problem relating to the starter as well – so you might want an inspection.
5. Alternator Belt Problems
If your alternator belt is growling, whining, creaking, or otherwise having issues, you probably have an alternator issue.
Here, you’ll also want to pay attention to smells like burnt rubber or burning plastic, because the alternator belt will start to rub and burn if something goes wrong.
Often, if this is the symptom you’re experiencing, you can simply replace the belt instead of replacing the alternator. However, you’ll still want a full inspection to be sure.
How Is An Alternator Replaced? (11 Steps)
Replacing an alternator is a relatively easy job providing you have a few tools. In most cases, you can complete the work in about an hour.
If you have a complicated system, you might have to remove a few things from on top of the alternator first. However, this is unlikely.
Things you’ll need:
- Ratchet set (usually in mm)
- Wrench set (usually in mm)
- Disposable gloves
- New alternator
- Fully charged battery
It’s important to prepare before installing your new alternator. Here, the most important step is to charge your battery or put a new battery into the car.
This prevents you from accidentally burning out the new alternator. If you don’t, you could ruin the new alternator as soon as you try to start the car.
You’ll also want to park the car on a flat and level surface, make sure you take the key out of the ignition (some cars lock all the doors and windows when you cut the power) and make sure you have a safe work space.
- Take the negative terminal off of the battery and tuck it out of the way where it is not touching metal.
- Disconnect the wires from the back of the alternator. Usually, these attach via a clip.
- Remove the belt from the pulley. If you have a tension pulley, you’ll have to attach a ratchet to the center of the pulley and ratchet it loose. Here, it’s a great idea to mark where the tensioner is before you take it off, so you can re-tighten to that point. White chalk or paint or even marker is a great option.
- Inspect the alternator and find the bolts and loosen them. They may be stuck, so get a breaker bar if you need it. Most alternators use a 14mm bolt on the top and a 12mm bolt on the bottom. Some models, especially older GM cars have three, which is 2 on the bottom.
- Double check that the new alternator is exactly the same as the old one.
- Slip off the fan or alternator belt and take off the electrical lead.
- Put the new alternator in place.
- Tighten the bolts.
- Slip the fan belt on.
- Tighten the 12mm adjusting nut until the fan belt is snug.
- Put on the electrical lead and tighten it.
From there, you can turn your vehicle on and test to see if that resolved your problems.
In most cases, it’s a great idea to replace the alternator belt while you have the alternator off. After all, taking the tensioner off is usually about half the work of the full job.
If you still have questions about replacing your alternator, these answers should help.
Can I drive my car with a bad alternator?
No. While it’s theoretically possible to drive your car, it’s actually quite dangerous to do so.
For example, most modern vehicles use power steering. Some also use electronically assisted brakes. If you stall or lose power while driving, you could lose control of steering and braking as well. This means it’s never a good idea to drive with a bad alternator.
However, it’s usually relatively safe to drive short distances such as to a mechanic where you can immediately have the alternator replaced. Just use caution, stay off of the Interstate, and drive slowly.
What kills an alternator?
Alternators can burn out for a few reasons, including trying to start with a dead battery. In other cases, the issue relates to age, power consumption, or simply failing parts.
In general, best practice to keep your alternator in good shape is to keep the battery in good condition.
What is the lifespan of an alternator?
Most alternators last 5-8 years on average, or 30,000 to 70,000 miles.
That might change depending on driving conditions and how much you use the car battery with the engine off.
How can I test my alternator?
You can use a multimeter to test the power output of the alternator directly.
Here, you want to set the multimeter to DC voltage above 15. Then, with the engine on and checking to be sure the positive and negative posts of the alternator terminals are clean, attach the clips. Look for a reading of around 12.6.
If your readout is lower than 12.4 you likely have an issue. And, if it’s significantly higher, that’s also true.
If your alternator is going out, it’s crucial to replace it as quickly as possible.
In most cases, changing your car alternator will cost around $800 including labor from your mechanic. That might drop as low as $350 or go as high as $2,500.
In addition, you can likely relatively easily do the work yourself if you prefer not to go to the mechanic.
Good luck with replacing your alternator.
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