Ticking in the Alternator

by Jay MotesUpdated July 13, 2023
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An alternator is responsible for supplying an automobile with electrical power and charging the battery. A ticking noise or clicking noise is often an indication that the alternator is about to fail. In order to diagnose this issue and determine if you have a bad alternator, here are some steps to follow to check your car’s engine.

Locating Sound

With an engine running, it can be difficult to determine the source of a ticking sound, especially if it’s just a single click every once in awhile. If it’s rapid clicking, that may be easier to locate and determine the culprit. A short length of tubing can be used to help locate the sound. By listening to one end of the tube while the other is placed near a possible source of the clicking, a person can determine the exact location of the noise. The component making the click will sound louder than the others.

Worn Alternator

An faulty alternator may make a clicking sound if the bearings or other internal components are beginning to wear on the alternator belt. Once the alternator has been identified as the source of the sound, remove the drive belt and turn the pulley by hand. If the pulley does not turn smoothly, the alternator regulator is worn.

Alternator Testing

To determine how poorly the alternator is performing, the alternator’s electrical system should be tested. This can be done with a voltmeter, but most auto parts stores will test the alternator for free. Parts stores can test the alternator either on or off of the car to determine if the battery terminals are just worn or if the car battery is just a dead battery and needs a jump-start.

The simplest way to test the alternator is to drive to the nearest auto parts store. Most auto parts stores will test the alternator for free and can test it without it removing it from the car. If this option is not available, the drive belt can be removed and the alternator pulley turned by hand to listen for the noise and feel for play.

Cause of Grinding Noise

As alternators age, the bearings that the pulley and the internal rotor turns on can become worn and the tensioner becomes less taught. As the bearings wear, the pulley begins to have slack that allows it to move side to side while spinning, creating the grinding noise. In addition to the noise, the alternator's electrical output in volts will begin to decline, which you’ll be able to see in the starter motor and feel in the power steering of the crankshaft.


Alternators can be expensive, but they are relatively easy to replace, which will reduce labor costs. Car owners with basic mechanical ability should be able to change their own alternators. Part stores sell both new and remanufactured alternators for most cars, with the re-manufactured units being considerably less expensive.

Video: Top signs 3 signs your Alternator Bad: How to find a ticking noise

Helpful comments on this video:

  • As a mechanic who works on all makes and models, i can say everything tears up!
  • Before you opened the hood, I said sounds like a decoupler pulley. Heard that on our old 2006 DGC. The bearings were still cool so I put a pulley on it. enjoy your stuff!!

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