Professional Mechanics Online Automobile Information Add Site to Favorites  


Auto Repair
Auto Repair Car Repair Home
Auto Repair Manual Auto Repair by Topic
Auto Repair Manual Auto Repair by Manufacturer
Auto Repair Talk Ask a Car Repair Question
Vehicle Repair Car Repair Video Series
Auto Repair Talk Car Repair Forum
Vehicle Repair How to Repair & Service
Vehicle Repair Car Repair Troubleshooting
Vehicle Repair How Does it Work?
Auto Repair Manual Discount Auto Parts
Vehicle Repair Online Repair Manual
Vehicle Repair Car Maintenance
Vehicle Repair Car Safety Information
Vehicle Repair Smog Test
Auto Repair Manual Diagnostic Trouble Codes
Vehicle Repair Engine Code Scanner
Vehicle Repair Avoid Car Repair Rip Offs
Car Repair Search Search Our Website
Car Repair Questions Auto Term Abbreviations
 
Search Website
 
 
Recent Forum Topics

 

Auto Repair1993 Mercury Marquis No ...
Auto Repair1994 Ford Ranger Warm En...
Auto Repair1992 Chevy Cheyenne Tens...
Auto Repair1999 Ford Escort While B...
Auto Repair1996 Honda Passport How ...
Auto Repair1991 Volvo 940 Replaceme...
Auto Repair1999 Ford F350
Auto Repair2000 Pontiac Sunfire Jus...
Auto Repair2005 Ford Expedition Lon...
Auto Repair1999 Lincoln Continental ...
Auto Repair2003 Ford Explorer Getti...
Auto Repair2000 Honda Accord To Dri...
Auto Repair2000 Chevy Malibu
Auto Repair1993 Mercury Marquis No ...
Auto Repair1998 Buick Lesabre Starting
Auto RepairMore Forum Topics...
 
Locate Auto Parts
 
 
Latest How-To Videos

  

Auto Repair Motor Oil and Filter Video
Auto Repair Engine Air Filter Video
Auto Repair Air Cabin Filter Video
 
 
 
 
 
     
 

Free Automotive Repair Advice by Certified ASE Technicians




How Does it Work / Alternator

Alternator and Charging System

A battery is needed to power the operating system of your car. Once the vehicle is running the battery is charged by the alternator which is driven by the engine. While in operation the alternator creates electricity, about 13.6 to 14.3 volts, and recharges the battery to it's original state of charge. The alternator is one of the hardest working electrical components in your vehicle. When your vehicle is running the alternator is busy creating electricity to provide the engine and the car accessories with needed power. When the car is not running and your battery is severely discharged some electrical components may still operate or operate poorly. Typically, these components are designed to operate properly at 12 volts, if the system voltage is low it can cause erratic symptoms.

Alternator
Typical Alternator



Common Problems and Solutions

When jump started a severely discharged battery can cause the alternator to overload and internally fail. If this occurs replace the battery before replacing the alternator. This will help prevent a second alternator failure. Most vehicles use a multi-ribbed belt connected to the engine to rotate the armature inside the alternator. If the belt fails it should be replaced immediately. Belt tension should be taught. If it isn't, check the belt tensioner. It may need to be replaced or the incorrect size belt may have been installed. Either of these conditions can cause the vehicle to stall and not restart.

Additionally, problems can occur if the alternator is overcharging the system. Some symptoms of overcharging include a swollen or seeping battery, both headlight bulbs failing at the same time, and other electrical component problems. To perform an alternator system check for this condition use a voltmeter on both positive and negative terminals while the engine is idling. If the voltmeter reading is over 15 volts this is an indication of an overcharging alternator. The alternator should be replaced with an OE (original equipment) unit. While an inferior rebuilt alternator is often much cheaper, it can fail prematurely causing another costly replacement.

The most common alternator problem is "undercharging." This condition is often accompanied by symptoms such as a low state of charge on the battery, poor or erratic performance from electrical components and dim headlights and other lighting systems. The first symptom of an undercharging alternator is a slow cranking engine. The next symptom is a "machine gun" sound when the engine is cranked as the system voltage drops below normal operating levels. In order to correct this problem a replacement alternator must be installed.

Maintenance

To ensure that your alternator lasts as long as possible there are several things you can do. Be sure all battery connections are tight and both terminals are clean.  This should be inspected periodically regardless of when the battery was changed as even new batteries can have problems and be defective. While the engine is off, visually inspect the alternator belt and replace the belt if cracks or tears are observed.

How Does it Work / Alternator

Check Manufacturer Specific Alternator Questions and Answers

Related Subjects

GET AN ONLINE REPAIR MANUAL FOR YOUR CAR. Get instant access to your vehicles drive belt routing, wiring diagrams, trouble code information, updates and factory bulletins.

Popular Service Repairs
Test Fuses
Front Brake Pads
Tune Up
Transmission Service
Rear Brake Pads
Rear Brake Shoes
Replace Window Motor
Test Alternator
Test Battery

Replace Air Filter

Check Engine Light

More Service Repairs...
Advertisement
Popular Question Topics
Alternator
Starter
Exhaust System
Fuel Economy
Rough Idle
Won't Start
Water Pump
Fuel Filter
Battery
Car Alarm
Multi Rib Belt
Catalytic Converter
Head Gasket
Intake Manifold
Motor Oil
Antenna
Air Bag
Fuel Pump
Seat Belts
Heater Core
Air Conditioner
Transmission
CV Axle Joint
Clutch
ABS
Front Brakes
Brake Rotor
Suspension
Oxygen Sensor
Mass Air Flow Sensor
Spark Plugs
Fuel Injector
Check Engine Light
EGR Valve
More Topics...
Popular Manufacturers
ACURA
ASTON MARTIN
AUDI
BMW
BUICK
CADILLAC
CHEVY
CHRYSLER
DODGE
FORD
HONDA
HYUNDAI
ISUZU
JAGUAR
JEEP
LAND ROVER
LINCOLN
MAZDA
MERCEDES BENZ
MERCURY
MITSUBISHI
NISSAN
OLDSMOBILE
PLYMOUTH
PONTIAC
PORSCHE
RENAULT
SAAB
SATURN
SUBARU
SUZUKI
TOYOTA
VOLKSWAGEN
VOLVO
More Manufacturers...

Car Repair Home l Help l Privacy Policy l User Agreement l About Us l Contact Us l Link to Us
  Copyright © 1998 - 2008 2CarPros.com - Professional Mechanics Online

Computer Repair