6 Symptoms of a Bad Alternator
Lights dimming? Battery dying overnight? Your car relying on battery power alone could point to alternator trouble.
Symptoms of a bad alternator make themselves apparent quickly. Keep reading to know what signs to look for, how long alternators last, and what the average replacement cost of an alternator is.
6 Symptoms of a Bad Alternator
Some points of failure affecting the alternator are bad bearings (which allow the rotor to spin freely) causing the rotor to seize, problems with the coils, and a bad belt (the rotor doesn’t spin right, so the alternator isn’t powered).
Of course, the way the vehicle indicates a problem is different depending on the root cause. If you have any of the following signs of a bad alternator, make sure to get it checked out quickly.
1) Vehicle Won’t Start/Dead Battery
The alternator doesn’t provide the power to start the vehicle – that’s actually the job of the battery. It does, however, charge the battery as the vehicle is running. If the battery can’t be charged, the car won’t start.
This is a tricky situation as the problem could be with the alternator or the battery itself, or even a plethora of other issues (bad starter, spark plugs, etc).
2) Squealing, Growling, or Other Noises From the Engine Bay
The alternator has spinning parts, and if movement of these is restricted (such as with bad bearings) there will be some odd noises.
Seizing of the rotor will cause a loud grinding noise, so make note of the sounds you hear and what’s happening with the car when you hear them in order to tell your mechanic. This information can give good clues.
3) Failing Electrical Systems
The electricity created by the alternator is also what powers the vehicle’s accessories such as air conditioner, power windows, power mirrors, stereo, heated seats, heated mirrors, headlights, entertainment, etc.
If you notice that any or all of these are not working well or at all, especially when the vehicle is at idle (since the RPM isn’t high enough to produce enough power if there are other issues), the alternator may be the cause.
You may also notice failing electrical gauges on your dashboard. Since those give you important information about safe driving conditions (i.e. speed) and the state of your vehicle (i.e. oil temperature) it’s imperative to stop driving as soon as possible and get the issue fixed.
Your alternator may even be overcharging which can bring more serious issues to the table.
4) Sudden Dashboard Warning Lights
Also due to the lack of sufficient power, you may notice warning lights such as the battery light, “check engine”, “ALT”, and/or other phantom lights show up on the dashboard.
When the ECU is starved of electricity, the brain can’t think well (much like you may feel when you desperately need a snack) so signals may be sent that are incorrect.
5) Stalling Engine
In newer vehicles, the engine may even cut entirely when it’s running because electronic fuel injectors need power to behave properly. It’s important for the right amount of fuel to be shot into the combustion chamber at the right time for the engine to run smoothly, so issues with this may stop the combustion cycle from continuing successfully.
6) Burning Smell
In severe cases, rubbing of parts or electrical issues within a bad alternator can cause a burning smell. Since you probably don’t want a fire under the hood, stop driving and get things checked out. Best case, the fusible link to the alternator melted (as it’s supposed to). Worst case, your alternator is toast.
