How To Change An Alternator In 10 Simple Steps


Having a car is always very convenient. However, there can be some days when it fails to start, and this can be extremely frustrating. Usually this is caused by one of two things: the battery is dead or the alternator needs to be replaced. Most people assume that it’s a battery issue and go out to get it replaced, only to find that their car still isn’t working for them. If this is the case, the alternator is the next thing to look at, and it is fairly easy to do yourself if you have the time at home. These instructions will not only save you from having to take your car into a shop, but they will also give your wallet a break.

  1. The first step is to disconnect the positive battery cable and locate the alternator in your car. The alternator usually is fairly large, about the size of a cantaloupe, and looks sort of like a big kitchen drain plug.
  2. Next, you are going to have to remove the belt with the assistance of a serpentine belt tool, and slowly move it off the pulley part of the alternator. This will give you much easier access to the bolts holding the alternator together, which is what you are going to have to work with in the following step.
  3. Loosen and remove the bolts holding the alternator together with a socket and ratchet tool. Depending on what kind of car you have, there may be anywhere from two to four bolts. It would be helpful to have a place near you to put the bolts so you don’t lose them while working on your vehicle.
  4. Next, carefully pull out your alternator and unplug it from any electrical connections. After that, remove the nut holding it together. At this point your alternator should be free from the car and not be connected to anything.
  5. Take the entire alternator out from the engine and place it into a bag or box. Now you are going to have to take it to your local auto parts shop or garage. Some people like to purchase the alternator in advance; however by doing it this way you are guaranteeing yourself that you will get the right one for replacement with the aid of a professional. Like most car parts, they can be somewhat expensive and the average alternator costs between $99 and $400, depending on what kind of vehicle you have. You are going to want to make sure that the one you buy has a voltage regulator and pulley to match the one you brought in exactly.
  6. Bring your new alternator home and put it in the exact place that you removed the old one from. At this point it is going to be a reverse process from when you removed the alternator.
  7. Connect the wires and electrical plugs into the new alternator just as they were in the old one before you slide the whole thing into place. Then find the bolts that you had put aside earlier and thread them into position before tightening them.
  8. Put the alternator pulley back to where it was and then go ahead and bolt it down. You will want to double check that everything is aligned correctly with the belt pulley.
  9. Next, use the serpentine belt tool that you had earlier to get the slack needed to put the belt back over the alternator pulling and release it once it is in place.
  10. Finally, reconnect your battery to the alternator, and start up the engine to make sure it works.

Written by Marc Laferierre, owner of Dents Unlimited. Dents Unlimited offers the best auto repair Columbia MO has to offer!