A bad alternator can leave you stranded at any time, so it’s important to know how to diagnose this potentially dangerous car part before you start experiencing strange problems with your engine.
The following list of 15 symptoms will help you determine if your alternator needs replacement or repair, if you notice more than three or four of these issues, it’s worth having your mechanic run a full diagnostic test on the alternator itself to ensure that it isn’t causing your car to overheat, stall out, or get poor fuel economy.
What is an Alternator?
An alternator is a component in a car that transforms mechanical energy into electrical energy. It’s connected to the engine of a car, and as the engine turns, it spins a rotor inside a magnet. This spinning creates an electrical current which is then used by the car’s various electrical devices.
If this device isn’t working correctly, your battery will drain more quickly than expected, and your car will have trouble starting if this happens.
List Of 15 Signs To Look Out for
1. The Engine Starts but Dies Shortly Thereafter
If the engine starts but dies shortly thereafter, it could be caused by a bad alternator; the first sign of an alternator that has gone bad is that the car will start but will not stay running.
When a car battery is used up, the alternator takes over to recharge the battery and keep the car running. If you hear clicking or humming when you turn on your vehicle, this could be an indication that there’s a problem with your alternation system.
2. Headlights Are Dim or Flickering.
Headlights are a common symptom of a bad alternator. If your headlights flicker or dim when you turn them on, or if the battery is drained at random times, it is likely that there is an issue with your alternator.
To diagnose this problem, you will need to start by checking the voltage coming out of the alternator’s terminal. If the voltage stays constant and does not drop below 12 volts after being charged for five minutes, then it is safe to say that the problem lies elsewhere.
3. Battery Warning Light is On.
If your battery warning light is on, pay attention to it. You may have a lousy alternator. The first step in diagnosing a bad alternator is to check your battery terminals and make sure they are clean and tight.
Next, you should check the voltage of the battery. If it is low, then you need to replace the alternator or at least have it tested by a mechanic.
4. Power Windows Are Slow or Not Working.
If your power windows are slow or not working, you may have a bad alternator.
One sign of a bad alternator is when the car battery is running low and the power windows stop working.
The other sign of a bad alternator is if you go to start the car and it doesn’t turn on.
The first step in diagnosing whether or not your alternator has failed is to pull out your battery cable for 10 minutes, then put it back in.
If the car starts up with ease after this time period, then there’s a good chance that your alternator has gone bad and needs to be replaced.
To diagnose a bad alternator, you can also do a voltage drop test by touching two jumper cables together while they’re hooked up to the positive post of one battery terminal and the negative position of another terminal.
You’ll notice an instant drop in voltage on one set of cables which indicates that something isn’t right with your charging system.
5. Car Accessories are Not Working.
You might have a bad alternator if your car accessories are not working. For example, your headlights might be dim, or your battery could be dead, but these could also be signs of something else, like a short circuit.
When diagnosing a bad alternator, you should first check for things that would cause the alternator to go out.
You may want to check the voltage regulator, a device that regulates the flow of electricity from the battery to the alternator and make sure it is in good condition.
6. The Car Stalls
If your car stalls out, this is a sign that something is wrong with the alternator. What maintains the charge in your battery is your alternator. And without it your car will not be able to start.
If you’re seeing this sign, you’ll want to head to a mechanic as soon as possible so they can figure out why the alternator isn’t working.
The lights on your dashboard are flickering: Flickering lights are often caused by an alternator issue because when an alternator fails, the voltage that gets delivered to other electrical components drops.
7. Grinding Noise When Starting the Car
A grinding noise when starting the car is a tell-tale sign that the alternator is bad. To diagnose if this is the case, take off one of the battery cables and touch it to an unpainted metal surface on the engine block.
If it sparks or there’s a loud crackling sound, then your alternator needs to be replaced, as it’s no longer providing any power.
Slow acceleration: When the alternator isn’t charging correctlycorrectly, you may notice that your car doesn’t accelerate as quickly as expected.
8. Burning Smell Coming From the Engine.
If the odour of burning rubber is coming from your car, it is most likely that you have a bad alternator. The smell of burning rubber is the result of an electrical short in the alternator.
This will often cause your battery to die and need to be replaced. In order to diagnose this problem, start by checking the battery fluid levels, and if they are low or even empty, you may need a new battery as well as an alternator belt replacement.
9. Engine Temperature is Higher Than Usual.
An alternator is responsible for regulating the voltage and amperage of the car’s battery. When an alternator goes bad, you will notice that your engine temperature will be higher than normal.
The simplest method to examine an alternator is to start the car and watch to see if the amperage gauge moves while it’s running. If it doesn’t move, then your alternator is not working properly.
10. Slow Cranking When Starting the Car
The first indication of a malfunctioning alternator is slow cranking when starting the car. When you attempt to start your vehicle, it should crank right away without any hesitation.
Whenever it takes longer than usual for your engine to turn over and get started, that means that the battery is not getting enough power from the alternator. The next thing you’ll notice is the headlights dimming while trying to start the engine.
11. Dashboard Lights are Dim.
If the dashboard lights are dim, this means that there is an issue with the alternator. Dashboard lights should illuminate brightly when the engine is started, and some of these lights will turn off as the engine winds down.
If your dashboard lights are dim and you can’t find any other issues, this could be a sign of a bad alternator. The engine starts but doesn’t want to stay running, so when your engine starts but won’t stay running, it is likely due to a problem with the alternator.
12. Alternator Belt is Loose or Broken.
When the alternator belt is loosed or broken, then the alternator may have been overworked, and it will need to be replaced. You’ll be able to see if the belt is loose or broken by inspecting it for cracks and fraying.
The belt should never be so tight that it’s cutting into the alternator’s pulley, but you’ll want to make sure there’s enough tension on the belt so that it doesn’t slip off of the alternator pulley.
If you don’t know how to inspect a belt, bring it to your mechanic, who can tell you whether or not it needs to be replaced.
13. The Car Won’t Start.
If your car doesn’t start, there are a few things you can check to see if it’s the alternator. The battery is the most common culprit for a bad start. Also, you are to check the battery and make sure it has enough power to turn over the engine.
If not, charge the battery or replace it with a charged one and try starting it again. If the car starts but doesn’t idle, that means the alternator isn’t charging properly.
14. Dead Battery
It’s not uncommon for a car battery to die. In most cases, the battery will just need to be recharged or replaced.
But if you get warning lights on your dashboard or you notice your headlights dimming while driving, it could mean that something is wrong with your alternator.
And if that’s the case, then you’ll need to take your vehicle in for an inspection.
15. Dim Headlights
Your headlights are the most important safety component of your car. If they aren’t working properly, you won’t be able to see the road ahead of you.
Headlights can be dim for a number of reasons, but one of the most common is a bad alternator. Your headlights should always have a consistent brightness that isn’t too bright or too dim.
Also Read: How to Change Spark Plugs (Step-by-Step Guide)
How To Diagnose A Bad Alternator
You can usually tell if your alternator is bad by checking to see if it’s producing electricity. Check the battery first, and then test the voltage at the battery terminal with a voltmeter. If it reads 12 volts or less, you probably have a bad alternator.
Next, disconnect the alternator from the belt and make sure that there’s no noise coming from it when it spins. If there is noise, then you probably have a bad bearing on your alternator, which will require replacement.
But if not, then your alternator needs to be replaced because it isn’t generating enough power for the car’s electrical needs. You can replace the old alternator with a new one as soon as possible; otherwise, your battery won’t last long.
The process of replacing an alternator takes only about 30 minutes and only requires hand tools.
Start by loosening the bolts around the top of the battery so you’ll have access to it easily, then pull off all six bolts holding down the metal clamp that holds down both halves of the alternator together.
Remove all wires attached to terminals before pulling out any clamps holding down wires, unhooking them from terminals, and clipping them back onto each side.
Then, use pliers to loosen up and remove the belt, unhook it from the crankshaft pulley, and detach it from both sides of the alternator.
Finally, remove the old bracket that holds down both halves of the alternator. You can use pliers again before installing a new bracket to hold it in place just like before.
FAQ
How can I tell if the issue is with the battery or alternator?
If you can start your car, but it dies shortly thereafter, your car’s alternator isn’t supplying enough power to charge your battery.
Try turning the headlights and interior lights on for a few minutes. If they dim noticeably or go out, then this is likely the issue.
But on the other hand, if there is no noticeable change in the brightness of these lights, then the battery may be dying. You should have your battery tested by a professional so you know for sure if it’s bad or not. Alternators will also test as bad.
Can a damaged alternator still power a car?
Although a bad alternator is technically still possible to drive with, it is not advisable as a bad alternator will drain your battery quickly.
With a bad alternator, you might still be able to drive around town, but on longer trips, you might end up stranded.
How common is a bad alternator?
Generally, a bad alternator will show signs of wear in seven years or 100,000 to 150,000 miles. The average cost to replace an alternator is $900-1000.
If you are experiencing any of the following issues and the vehicle is less than seven years old, it’s worth checking with your mechanic before deciding whether or not to replace the alternator.
Also Read: How to Stop Car Engine Stalling
Conclusion
A bad alternator can cause a lot of problems for your car, and If you observe any of the above indications on your car, then it’s probably time to get your alternator checked out. As in the above guide, it has been explained what an alternator is and how it works, so you are employed to read carefully and make use of the diagnosis stated