There are certain parts of your car that, if removed, render your car immediately useless. Without the wheels, your car won’t roll. Without the transmission, it won’t move. Then, there are other parts, that if removed, wouldn’t make a bit of difference in getting you to your destination. Your car will handle the same without its tail lights, rear seat, or radio. Then, there are some parts that if removed, will eventually disable your car. Your alternator is one of those parts.
Let’s say you remove your alternator. Your car will still start off the battery, and you’ll be able to drive it… for a while. As you drive down the road, you’ll start to deplete the battery as it provides power for your sparks. You’ll run the battery down even faster if you’re using other electrical consumers, such as your tail lights or radio. When your alternator fails, you often get little notice other than an ignition system warning light in your instrument cluster. If you don’t notice the warning light, and keep driving, eventually you’ll kill the battery and your car will stop running.
If you’re unsure of your alternator‘s condition, you can give it a quick test with a volt meter. With the engine running, you place one of the volt meter’s terminals on the alternator‘s positive power post and touch the other terminal to a vehicle ground. A properly functioning alternator should give a reading of around 14 volts.
Thankfully, an alternator is an easy DIY replacement item. Although placement will vary by make, manufacturer, and model of car, they tend to have a lot in common. Most alternators are mounted to a bracket with a single bolt on which the alternator can pivot, and another one which provides tension for the alternator belt. The alternator pulley is powered by a belt driven off the crankshaft. Sometimes this belt will also power another accessory, such as the A/C compressor or the power steering pump. You may have a belt drive system with multiple belts powering multiple accessories, or your engine might have a single serpentine belt powering all the accessories. Your car’s alternator might be mounted right near the top of the engine compartment, or it might be low enough that you need to put the car up on ramps or jack stands in order to change it.