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Home >   How To >   How to Repair Alternator >   Symptoms of a Damaged or Failing Alternator

Symptoms of a Damaged or Failing Alternator

 

The alternator supplies power to a vehicle’s electrical components like the headlights. The alternator tends to fail gradually, and its warning signs can signify future breakdown long before it occurs. Diagnosing a problematic alternator early can save you from a world of trouble. Avoid ignoring the tell-tale signs, and get the problem fixed before you’re stuck with an inoperable vehicle. Here we have explained some of the prominent symptoms and causes of worn-out alternators.

 

 

Alternator

 

Symptoms of a Faulty Alternator

 

Difficulty Starting/Runs Rough

 

It requires a good deal of energy to crank the car’s motor, and if a battery is not replenishing its power properly due to a faulty alternator, it will become drained and ineffective. You will hear a clicking noise while attempting to start the car, and the engine will have difficulty turning over. The initial course of action is to check your battery, be sure to check your alternator for problems, as well.

 

Degrading Performance of Electrical Components

 

This warning sign is less obvious, but will progress in frequency. Over time, it will become evident that the alternator needs attention. Electrical components in the car will slowly start showing signs of failure: the headlights and dashboard lights will dim or the power windows will roll slower than usual. Eventually, these electrical components will cease to operate completely.

 

Growling or Whining Noise

 

The alternator is driven by a belt in conjunction with the crankshaft pulley. The alternator pulley typically spins about two times faster than the crankshaft pulley to produce the necessary power for the vehicle at lower engine speeds, especially while idling. If the pulley is not in correct alignment with the belt, or if the bearings are won out, the alternator will make a growling noise. Be sure to perform a visual preventative check of the belt for cracking, excessive wear and other age-related issues.

 

Smell of Burning Rubber

 

The scent of burning rubber or scorched wires sometimes indicate an alternator failure. Friction between a misaligned belt and the pulley will emit a smell of burning rubber. The burning wire smell can be caused by an overheated alternator.

 

Warning Light

 

When your alternator does not perform up to its usual standard, the ALT or GEN light in your automobile's instrument panel will light up. If the electrical components of your vehicle do not seem to have their original potential, it is recommended that you check your alternator along with them.

 

Causes of a Bad Alternator

 

  • One of the most common problems of a faulty alternator is a loosened belt.
  • The diodes of the alternator can go bad, failing to transmit the required voltage.
  • The bearings on which the alternator rotates can also be at fault and hinder the alternator from providing an optimal performance.
  • If there is any problem in the field voltage received by the alternator, it will not function up to its optimum potential.

 

Most times, you might be confused as to whether the problem is with your car's battery or alternator, as they work hand-in-hand with one another. The following tests can help you ascertain the actual defective part:

 

  • Allow the engine to run and remove the negative cable of your vehicle's battery. If you notice the automobile stalling, the problem is with the alternator. Otherwise, the problem lies with the battery.
  • Start your vehicle and have someone check the headlights. With the vehicle in “park” mode, press the accelerator pedal. If the headlights dim in intensity or turn off altogether, the problem is with the alternator. If not, the alternator is probably doing its job fine.

 

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