The Toyota Corolla uses an alternator to run electrical devices in your vehicle while the engine is running. A voltage regulator maintains a constant voltage level and is frequently integrated into the alternator assembly. If your battery continually runs down or your headlights become dimmer while the engine is running, you may need to replace the alternator.
Determine which alternator your Toyota Corolla needs. Be sure the new alternator is compatible with your Corolla's engine. Models made from 1966 to 1970 have a 1.1 L or 1.2 L engine. Models built from 1970 to 1978 have a 1.2 L, 1.4 L or 1.6 L engine. Models made from 1979 to 1987 may be equipped with a 1.3 L, 1.6 L or 1.8 L diesel engine.
Look at later versions of the Toyota Corolla. 1988 to 1992 options include a 1.3 L, 1.5 L, 1.6 L or 2.0 L diesel engine. Models made from 1993 to 1997 also offer a 1.8 L engine. Models from 1998 to 2005 in the United States were available only with a 1.8 L engine.
Examine the latest generation of the Toyota Corolla. It debuted in 2006 and is available with a 1.5 L, 1.8 L or 2.4 L engine.
Disconnect the negative battery cable with a socket wrench. Remove the gravel shield if you need to access the alternator from under the car. Remove the electrical connector and unfasten the retaining nut on the alternator terminal with a socket wrench. This allows you to remove the battery terminal wire.
Remove the drive belt. Unfasten the two mounting bolts on the alternator with a socket wrench and take the alternator off the vehicle.
Install the new alternator assembly. Use a torque wrench to tighten the smaller mounting bolt to 18 foot-lb. and the larger one to 40 foot-lb.
Connect the electrical harness and battery terminal wire to the alternator and fasten the retaining nut to the alternator terminal with a socket wrench. Install the gravel shield if you removed it. Replace the drive belt and restore it to the proper tension. Reconnect the negative battery cable with a socket wrench.