How Do You Know If You Need a New Alternator?

If your car doesn’t have enough juice to start, chances are you need a new alternator. The alternator--supported by a voltage regulator--is part of your car’s engine that produces electricity. It uses mechanical energy from the engine and battery.

An old alternator can cause all kinds of problems with your car. Not only will you notice your headlights flickering, you may end up having starting issues. If you are wondering if your car needs a new alternator, you can make some diagnostic checks to find out for sure.

Check the Battery

If you are wondering if you need one of the high output alternators available for sale, start by checking your battery. If the battery is old, it may not have enough power to run the car. Therefore, if you’re having problems with starting, it may be due to the battery.

If the battery is corroded or you notice pitting, you’ll need to replace it. Most batteries reach their lifespan after 3 to 5 years. Otherwise, take a look at your alternator.

Are you starting your engine, but it fades out quickly? If so, the problem probably has to do with your alternator. However, if you jump start your car, and it keeps running, but the car won’t restart again, you’ll most likely have to get a new battery.

Check the Fuse

If you are wondering if you need a new alternator, you might also check for a blown fuse. If a fuse has blown, the alternator probably isn’t putting out enough power to run your car.

Listen for Strange Noises While Turning Over

Listen for strange noises while turning over the engine. If you notice a grinding or popping noise during starting, a bad bearing in the alternator may be the problem. Do you hear a squealing noise during starting? If so, the belt may not be tight enough, or it needs to be replaced.

Use a Multimeter to Check the Volts

You should have a multimeter on hand for testing your alternator. You can use this practical device to measure household current and electrical connections in your car. While you can use fancy machines, such as load testers, for the work, this can get pretty expensive - at least $2,000. Therefore, if you’re a DIYer, the multimeter is a great device for getting more insight on your alternator’s condition.

How to Use a Multimeter to Check Your Alternator’s Condition

By using a multimeter, you can check your alternator’s condition by applying the multimeter’s prongs to the battery’s terminals. Do this when the vehicle is shut off. The reading should fall between 12 and 13 volts.

Start up the vehicle again and check the battery’s voltage. This time, the reading should be about 13S, which equates to 48 volts. Taking this step will tell you if your alternator is working properly, or producing enough volts.

Some Major Warning Signs

While using a multimeter can help you confirm the alternator’s function, you’ll get quick warning signs that don’t necessarily need a multimeter test. If your alternator is between 7 and 10 years of age, you should replace it, even if you’re not experiencing problems now. Chances are you’ll experience them in the near future if you don’t make the switch.

Mileage and Length of Life

The 7-to-10 year estimate for longevity equates to an odometer reading of about 80,000 to 150,000 miles. However, in some cases, you may need to replace your alternator sooner, especially if you drive your vehicle frequently.

Low Battery Warning

Besides problems with starting, you may see your low battery warning light spring to life on your dashboard. This is a sure sign your alternator is failing.

The Smell of Burning Rubber

The smell of burning rubber beneath the hood is another tell-tale sign.

Both of the above forecasts are just indicators that your alternator has seen better days.

The Type of Part - Aftermarket, OEM, or High Output

If you’re used to using aftermarket parts instead of OEM parts, you’ll usually have to make a switch sooner as well. Also, if you replace our alternator with the high output variety, you’re going to keep your vehicle running longer.

Recap: Dead Battery vs Failing Alternator - How to Know for Sure

You’ll need to figure out if the problem has to do with a dead battery or the alternator. Again, when your car does not start, give it a jump-start. If it dies right after you remove the cables, the alternator is usually failing. However, if it continues to run, you’re typically dealing with a battery issue instead.

If Starting Is a Problem, Use the Above Tips

The alternator charges the battery and sends power to other electrical components in your car’s system. Therefore, a bad alternator can drain your battery and make it difficult to start your car. You can test your alternator to see if it is working properly by using the above tips. Preventive maintenance and regular system checks will help you avoid costly car repairs over time.