NAPA Auto Parts Sterling, VA
45449 Severn Way
Sterling,  VA  20166-8918
(703) 378-6666
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Mon-Fri:8:00 AM-6:00 PM
Sat:8:00 AM-3:00 PM
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Car Alternators & Starters

Part Types

Power Generated

Alternators for cars, which are essentially small generators, are a crucial piece of the electrical system. They maintain the charge on your vehicle's battery by feeding it a regulated current of electricity. Car alternator parts include a voltage regulator, stator, rotor and diode. Other important components are:

      • Pulleys
      • Housing
      • Stators
      • Starter solenoids
      • Foot switches
      • Connectors
      • Rectifiers or diodes
      • Alternator insulators
      • Belts

When you start your car, the power from the battery turns the starter, which then turns the alternator belt from the accessory drive, spinning the pulley on the alternator. The alternator's rotor is comprised of a series of magnets that rotates quickly and produces an alternating current (AC), which is converted into direct current (DC) using the rectifier or diode. The voltage regulator ensures that the right amount of electrical current is flowing to the car battery, so that it does not get overcharged or drained.

Taking Off From A Cold Start

Car alternator problems crop up more frequently in the wintertime, because cold weather makes it more difficult for a battery to produce power. On a warm spring day, the alternator would only need about 20 minutes of driving to fully recharge the battery. In winter, it can take much longer, which is why it's a good idea to let your car warm up on a chilly morning.

Do you notice a squeal coming from under the hood when you start your car on a cold day? Most of the time this noise eventually goes away, because the belt that drives the alternator is cold and rigid, causing slippage, which creates a squealing. As the rubber of the belt warms up, it makes improved contact with the pulley, and the noise disappears.

When The Lights Go Down...And Up, And Down Again

What are the symptoms of a bad alternator? Dashboard lights and headlights that flicker, dim or brighten are hard to miss. This is the result of an unstable electrical current if the battery is in good shape, the next culprit is normally the alternator. Use a little NAPA Know How to check out our selection of voltmeters and perform a test on your Ford F150.

Check the voltage of your battery: it should be between 12.5 and 12.8 volts with the engine off. If it's lower than that, charge the battery with a charger prior to conducting the test a second time. Start the engine to check the meter for increased voltage. If the voltmeter reads between 13.8 and 15.3, it should mean the alternator is performing correctly. If it's time for an alternator replacement, NAPA AUTO PARTS carries a vast supply of alternator repair kits, condensers, bracket clamps and even rectifiers and brushes for all your alternator repair or replacement needs.

How To Avoid A Non-Starter

Modern internal combustion engines must work in harmony with an intricate electrical system. The heart of this system is the starter motor, a powerful electric motor that is used to 'crank' or 'turn over' an engine. The main parts of a starter motor are:

      • Solenoid
      • Actuating arm
      • Field windings
      • Commutator
      • Brushes

The pinion has teeth like a gear that marry to the teeth of the flywheel on the engine, which rotates in unison to turn the crankshaft. When you turn the key in your Honda Civic, the ignition switch is engaged, and the power from the battery is delivered to the solenoid, which sits on top of the starter motor itself. The circuit from the battery to the motor is completed, causing the motor to spin.

What are the symptoms of a bad starter? If the starter sounds like it's struggling to turn the motor over, be sure to check the voltage on your battery first. If the battery is still supplying power, you may have a starter problem. If your headlights or the electronic displays in your dash are dimming as you turn the key in the ignition, this could also point to a starter issue. If the starter is getting power but not engaging the engine, it's likely that the pinion has disengaged from the flywheel, and the unit will need to be replaced.

Are you hearing a grinding after you start the car? That could be pointing to a gear problem within the starter, which will need a closer look. If you're ready to diagnose and fix the problem yourself, NAPA AUTO PARTS offers a huge selection of remanufactured and new replacement starters, as well as components and tools to get the DIY job done. If you'd prefer to leave it up to our NAPA technicians, check out any one of our numerous NAPA AutoCare Centers nationwide!