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How To Repair Alternator: What everyone should know about

While everyone knows where their battery is and even how to replace it if they have to, they often have no idea about how to repair alternator. This is part of the system that keeps your battery charged. In fact, the two parts rely on each other.

If your alternator is bad, you may think it is the battery.  Here’s what you need to know to figure out what’s happening and whether your car needs alternator repair. 

Why is an Alternator so Important?

The battery is charged by the alternator while the car is running.  It essentially takes the mechanical energy from the car’s engine and changes it into electrical energy. Alternators have AC power, which can change direction as needed. This alternating current is kickstarted when the car is turned on, activating the battery. 

(Source: https://www.roadandtrack.com/car-culture/a36386503/how-to-test-alternator/)

The battery communicates energy to the alternator.  Quickly, the alternator takes over. It sends energy to the battery and to other electrical components, such as the radio, power chairs, touchscreen, electric fan, and more.

In old cars, there was a component called a voltage regulator. Today’s ECU, the car’s computerized system, regulates the alternator’s energy output. 

The Seven Indicators that Alternator Repair is Needed 

An alternator can let you know it’s going bad. It can also die suddenly. Here’s how to stay alert to signs of a bad alternator, according to the seasoned mechanics at Earnhardt Auto Centers

Low Battery Voltage 

If the battery registers low voltage or is simply dead, the battery is either dying or not getting charged.  When checking a cold battery, the voltage should be 12.4 to 12.8 volts.  More importantly, while driving, the voltage should be 13.7 to 14.7 volts.  If your battery is showing up with a low cold voltage and isn’t achieving the 13 mark while driving, it is likely you need a new battery. Keep reading, however, to determine if the problem goes further. 

Dim Lights

If you suspect there is a problem with your battery, you should check how bright your lights are when you first turn the car on.  If they are dim, there is something going on with the electrical system.  If they get brighter when you rev the engine, then the problem may be the alternator rather than the battery.

Bad Battery

If you have a newer battery, but it keeps dying, this may indicate that the alternator has gone bad.  Remember that the battery and alternator are reliant on each other. If one goes, it may take the other one with it.  The best way to avoid this is to change your battery at the recommended interval and keep an eye on its voltage.

Engine Noises

If you hear a squeal or growl from under the hood, it could indicate that the bearings have worn out.  This would cause the rotor to have trouble moving, leading to some loud grinding noise. There are other parts as well that could generate similar noises.  You should report this to a mechanic.

Dead Accessories

You have so many accessories that are powered by your battery and alternator. There are so many more than there were 20 years ago.  This includes your touchscreen system which is a big power drain.  Your electrical gauges are another newer invention that needs power and won’t work if there is a system problem. Then there are accessories such as the power windows, power locks, power and side mirrors.  Your air conditioner may stop working because there isn’t enough current to run the fan.  

All of this is a sign that the car may need alternator repair, especially if the problem occurs when the car is idling.  The alternator may start to produce enough power while on the road, but the problem will only get worse if it is not repaired.

Dashboard Lights

There are several lights that can indicate an alternator problem.  You might see the ALT light or it could be ‘check engine’ or ‘battery’.  There are other lights that could come on due to an ECU malfunction. Without enough electricity, the system may get mixed signals. The good news may be that a new alternator will clear up all confusion.

Apparent Engine Failure

Your engine may not be able to run at all if the alternator has quit working. This is due to such components as the electronic fuel injectors.  As soon as power is restored, they should work again. However, time is of the essence.  The sooner you can get the alternator replaced, the better of the related engine components will be. 

How To Repair Alternator?

There are three options for you to choose on how to repair alternator:

  • Replace your old alternator with a new one
  • Replace your old alternator with a used one
  • Repair your old alternator

It’s advisable to take your vehicle to an auto repair service to have your alternator checked and repaired. However, you can absolutely do it if you’re a DIY mechanic and you’d love to repair it on your own. Please be noted that some experience around cars is desirable, especially some advanced knowledge if you want to do the complete alternator repair yourself. 

How Much Does Alternator Replacement Cost?

The average car alternator is $300 or less. However, luxury car alternators may be as high as $1,000. If your car is old, you can consider saving money with a remanufactured or rebuilt alternator.  Labor costs will depend on how difficult it is for the mechanic to gain access.

An alternator should last 80,000 miles or more.  That’s five to eight years, depending on driving habits. However, high-tech devices have been shown to affect the lifespan of the battery and alternator.

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