The BMW 325i is built for performance and comfort, and both of those things are centered around the electrical system. An integral part of that system is the alternator, which is responsible for charging the battery of the car and changing the electrical current that the car uses. The alternator is located at the top of the engine, and removing it is a straightforward job that requires only a few basic tools.
Disconnect the positive and negative terminal on the battery with a socket wrench. The location of the battery depends on the year of your BMW. The battery may be under the hood or under the back seat.
Open the hood if not already open. Locate the alternator belt on the front of the engine.
Loosen the tensioner with a socket wrench. The tensioner is under the alternator pulley. Pull the belt off the alternator pulley.
Unplug the wires at the back of the alternator by pulling them away from the connector. Make sure that all wiring is disconnected from the alternator.
Unscrew the two bolts securing the alternator to the mounting bracket, using a socket wrench.
Lift the alternator out of the engine compartment.
