How long does it take to replace an alternator? In most cases, this job takes one to two hours. The alternator attaches to the side of the engine, and is driven by a belt. To remove the alternator, the belt is removed, the wires are disconnected, and the alternator is unbolted from its bracket. Installation follows these steps in reverse order. Of course, accessibility varies from model to model. On some cars, the alternator is mounted high, so it’s easy to access with the hood open. On other models, underbody panels and other components may need to be removed to get access to this part.
