Your vehicle’s alternator keeps your battery charged and powers your electrical accessories. Unfortunately, a failing alternator can leave you helpless on the side of the road. If you suspect a problem with this part, you may want to learn how to test a car alternator.
Signs You May Need To Replace Your Alternator
The alternator is one of the main components of your car’s electrical system. Often, if it’s beginning to fail, you may notice any one of these symptoms:
- Illuminated Dashboard Indicator Light
Modern cars have dashboard indicator lights for many car systems. If you see one that looks like a battery, you have a problem with your car’s charging system. This may be a failing alternator, but it can also indicate an issue with your battery.
- Dim Lights
A failing alternator can’t generate enough power to keep your lights powered at full strength. You may also experience problems with other accessories that draw electricity.
- Unusual Noises
Converting mechanical energy into electricity requires spinning magnets. However, moving parts create friction. Thus, the alternator contains ball bearings to allow the magnets to spin smoothly. Over time, these bearings wear out creating more friction and unusual noises. You may hear whining, grinding, screeching, or rattling sounds.
- Frequent Stalling
Both the spark plugs and fuel injectors require electricity to function properly and keep your engine running. A failing alternator can’t supply enough electricity to these parts causing stalling of the engine.
- Trouble Starting Your Car
When you turn the key in your ignition, it’s the battery that gives your engine a jolt of electricity to start it. However, it’s your alternator that keeps your battery fully charged. If your car won’t start, you could have a problem with either part.
How To Test A Car Alternator With A Multimeter
If you suspect a problem with your charging system, you can perform a test using a multimeter. This tool measures the voltage, current, and resistance of electrical devices. Moreover, learning how to test a car alternator with this tool is a simple process. You’ll want to perform the alternator check both with the engine off and with it running:
- With your car engine off, turn on the multimeter and set it to DC.
- Connect the positive lead (usually red) to the positive battery terminal and the negative lead (usually black) to the negative terminal.
- Check your voltage meter. A fully charged battery will be at 12.6 volts
- Now, start your car.
- Recheck your multimeter. It should read between 13.5 and 14.5 volts.
- Turn on some accessories and check to see if there’s a reduction in voltage.
Although many people use this test, it really isn’t a good indicator of the health of your charging system. It just shows that the battery isn’t receiving electricity from the alternator. A blown fuse, bad wiring, or aging serpentine belt can all affect your alternator.
When you’re performing an alternator check, inspect your belt for signs of cracking or fraying. Any damage may cause it to slip. The tension can also cause problems if it’s not set at the ideal setting. If you suspect a problem, bring your automobile to your mechanic to check your belt, fuses, and wires.
Protect Your Auto Parts With Recommended Maintenance
Often, car owners can extend the life of certain auto parts by performing routine servicing. For example, batteries only last about 3-4 years and a dying battery can strain your alternator. Checking the charge of your battery and replacing it as needed can protect your alternator.
Of course, we all know about the importance of regular oil changes. However, when you visit Havoline® Xpress Lube of Kernersville for this service, we’ll also perform a courtesy check:
- Engine air filter
- Brake fluid
- Power steering fluid
- Automatic transmission fluid
- Coolant/antifreeze
If we notice anything wrong with the serpentine belt, wires, or battery, we’ll let you know. Plus, if you have any other concerns, we can take a look at those components.
FAQs About Car Alternators
Do you have some questions about car alternators? Below, we answer a few commonly asked ones.
When Should I Replace My Alternator?
Most experts agree that an alternator should last between 80,000 and 150,000 miles or about 7-10 years. However, a bad belt or battery can strain the alternator shortening its life.
Can I Drive With A Failing Alternator?
Driving with a failing alternator is a dangerous idea. Not only could you become stranded, but as you’re driving, you could lose power to parts requiring electricity. Imagine driving along a dark road and your headlights go out. Or speeding down the highway and having your power steering go out.
Furthermore, you may cause serious engine damage. Many of today’s modern cars use electric water pumps along with radiator fans to keep the engine cool. When your alternator dies, these parts lose electricity and stop working. Without a working cooling system, your engine will quickly overheat.
How Much Does It Cost To Replace An Alternator?
A new alternator can range in price from $100 – $350. This cost depends on the make, model, and whether it’s an aftermarket or OEM part.
Of course, any additional repairs will also drive up your cost. However, before we begin any major repairs, we’ll give you an estimate. We’ll also take the time to explain your issues in easy-to-understand language.
So, instead of trying to learn how to test a car alternator, bring your car to Havoline® Xpress Lube of Kernersville. Call us today at 336-993-7697 to make an appointment.
