The alternator is one of those parts that, when it malfunctions, can leave you high and dry by the side of the road. This essential component of your vehicle’s systems turns mechanical energy into electrical energy, which in turn, powers electrical systems in the car. Most importantly, the alternator charges the battery, which is why when this part goes bad you will not be able to start your car.

Most alternators eventually just wear out. Signs that your alternator needs replacing include:

  • Illuminated “ALT” light on the dash
  • Squealing, whining, or growling due to a bad belt or bearings in the connection between the alternator and the crankshaft
  • Rough idling or other abnormal engine behavior
  • Lights dimming or flickering due to the interruption in electrical power

How to make sure you’re getting a good quality alternator:

  • Check the part number: The required information for getting the correct part can usually be located on the alternator itself. If not, call a dealership with your VIN and they will tell you exactly which one you need.

  • Purchase from a reputable dealer: This is one part you don’t want to have to replace frequently, so whether you’re buying online or in a brick-and-mortar store, make sure you’re purchasing from a well-respected source.

  • Get the longest warranty possible: Defective alternators aren’t unheard of, and the repair is intensive and expensive enough that you’ll want the best possible guarantee that your part is high quality and will be replaced if it malfunctions.

  • Shake the alternator: It sounds odd, but if there’s any kind of rattling or clicking, ask for a different one.

Alternators can run anywhere from $100 to several hundred dollars new, so this is one part that you may consider purchasing as a rebuilt. If you do go this route, consider these precautions:

  • Use a voltmeter to power test the rebuilt part. If you buy from a store, have them test it for you.

  • Get a warranty. Even rebuilts can come with warranties, and particularly in the case of refurbished parts, you want that extra assurance.

  • Know the source. Find out where the alternator came from, if at all possible. Even a reconditioned part only has a limited number of miles that it will last, so if it’s fairly close to the end of its life you’re better off investing in a new one.

YourMechanic supplies top-quality alternators to our certified mobile technicians. We can also install a alternator that you've purchased. Click here to get a quote and more information on alternator replacement..

This article originally appeared on YourMechanic.com as How to Buy a Good Quality Alternator and was authored by Valerie Johnston.


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