How to Replace the Alternator in a Pontiac Grand Prix

The Pontiac Grand Prix has an alternator that sends electrical current to various devices in the vehicle while the engine is running. Most alternators made today include a voltage regulator that ensures the voltage level remains constant. You may need to replace the alternator if your battery keeps running down or your headlights become dimmer while driving.

Instructions

1

Determine which alternator your Pontiac Grand Prix will need. You'll want to be sure the new alternator is compatible with your Grand Prix's engine. Models made from 1962 to 1968 will have a 389 cubic inch (ci), 400 ci, 421 ci or 428 ci engine. Models built from 1969 to 1972 may be equipped with a 400 ci, 428 ci or 455 ci engine.

2

Look at later generations of the Pontiac Grand Prix. Models made from 1973 to 1977 may have a 231 ci, 350 ci, 400 ci or 455 ci engine. Models built from 1978 to 1987 have 231 ci, 252 ci, 265 ci, 301 ci, 305 ci and 350 ci engines. Models manufactured from 1988 to 1996 can be equipped with a 2.3 L, 2.8 L, 3.1 L or 3.4 L engine.

3

Examine the most recent versions of the Pontiac Grand Prix. Models made from 1997 to 2003 will have a 3.1 L or 3.8 L engine. The last generation was produced from 2004 to 2008 and had a 3.8 L, 3.8 L supercharged or a 5.3 L engine.

4

Disconnect the negative battery cable and the accessory drive belt with a socket wrench. Remove the engine sight shield if you have a 5.3 L engine.

5

Unplug the electrical connectors from the alternator. Unfasten the nut for the positive battery terminal with a socket wrench and remove the battery wire from the terminal.

6

Remove the bolts from the rear brace and mounting bolts for the alternator with a socket wrench. Remove the alternator assembly.

7

Install the new alternator assembly and tighten the mounting bolts to 37 foot pounds with a torque wrench. Connect the electrical connectors and battery terminal wire to the alternator and torque the retaining nut to 15 foot pounds. Install the rear alternator brace and torque the bolts to 37 foot pounds. Install the drive belt and the engine sight shield for a 5.3 L engine. Connect the negative battery cable with a socket wrench.