While your spark plugs and battery work together to create ignition, its actually the alternator that's responsible for most of the electricity used by various systems and parts. It does that by taking the engine's mechanical energy and converting it into electrical energy.

How Does an Alternator Work?

A crankshaft takes the engine pistons' vertical motion and transforms it into rotary motion. That in turn activates a belt that's attached by a pulley to your rotor shaft. The rotation of the shaft agitates magnetic coils contained within, which produce a magnetic field as a result. A rectifier captures that as AC power and converts it into the DC power that operates such parts as your windshield wipers, power windows, sound system.

How Do You Spot Alternator Issues?

Unfortunately, alternators can go bad. If that happens, your battery becomes your sole source of electricity. Once it drains -- and it will -- you're at great risk of being stranded by the side of the road. Signs of trouble include:

Dim or flickering headlights
Sound system problems
Power windows quit working
Whining noise coming from your engine
A burning smell from under the hood
Your battery keeps dying

What Alternators Are Best?

To test for a failing alternator, check the battery's voltage when the engine is turned off. If it reads below 12.5 volts, charge it and test again. If your voltage readings aren't higher the second time you check, your alternator may be going bad. In general, alternators only last about seven years -- or between 100,000 and 150,000 miles. After that, you're taking a chance. An alternator made by your manufacturer is your best choice, since it's designed to work with your model. Find yours in our online Subaru auto parts inventory. Buy today and we'll ship your order right to your door!