How to Replace the Alternator in a VW Jetta

Determine which alternator your VW Jetta needs. Be sure the new alternator is compatible with your Jetta's engine. Models made from 1980 to 1984 have 1.6 L or 1.7 L engines. Models built from 1985 to 1990 had a 1.8 L engine, and models made from 1991 to 1998 may be equipped with a 1.6 L, 1.8 L, 2.0 L or 2.8 L engine.

Look at recent models of the VW Jetta. Models manufactured from 1999 to 2004 have 1.4 L, 1.6 L, 1.8 L, 2.0 L or 2.8 L engines. The current version debuted in 2005 and may have any of the following engines: 1.4 L TSI, 1.6 L FSI, 2.0 L FSI, 2.0 L TFSI or 2.5 L.

Disconnect the negative battery cable with a socket wrench. Label the wires, if necessary, and remove the electrical wiring from the alternator.

Reduce the belt tension so you can remove the drive belt from the alternator. If you have a 2.5 L engine, you will then remove the mounting bolts with a socket wrench. Otherwise, use a socket wrench to remove the adjustment bolt and then the pivot bolts for the alternator. This allows you to carefully detach the alternator from its bracket.

Install the new alternator assembly on the bracket. Install the upper mounting bolt on 2.5 L engines with a socket wrench. Otherwise, fasten the pivot bolt and loosely install the adjustment bolt. Place the drive belt on its pulley and adjust the tension. Tighten the bolts.

Connect the electrical wiring as indicated by your labels and connect the negative battery cable with a socket wrench.