How to Fix an Alternator in a 99 Alero

The alternator on the 1999 Oldsmobile Alero 2.4-liter four-cylinder engine is a non-serviceable unit, which must be replaced if it fails for any reason. The alternator sits just above the air-conditioning compressor and is driven by the accessory drive belt. Replacing the alternator will require removing the accessory drive belt. When changing the alternator, the accessory drive belt should be inspected and replaced as necessary.

Instructions

Removal

1

Lift the vehicle hood and support it with the prop rod. Draw on paper the accessory and belt routing with the pen. Disconnect the negative battery cable with a wrench.

2

Attach a 13 mm socket to the breaker bar. Attach the breaker bar and socket to the bolt on the tensioner pulley and rotate the pulley counterclockwise to relieve tension on the drive belt. Remove the drive belt and release the tensioner pulley.

3

Disconnect the wiring harness from the plug on the alternator housing by lifting on the plastic tab and gently pulling it out of the plug. Disconnect the wire from the side of the alternator housing by removing the securing nut with a wrench.

4

Remove the bottom bolt securing the alternator to the alternator bracket with the socket and ratchet. Support the alternator by hand and remove the upper mounting bolt and upper mounting stud with the socket and ratchet. Remove the alternator from the engine.

Installation

5

Set the alternator into place and hand tighten the mounting bolts and mounting stud. Tighten the alternator mounting bolts and stud to 37 foot-pounds of torque with the torque wrench.

6

Attach the wire to the terminal connector on the housing of the alternator and secure it with the retaining nut. Plug the wiring harness into the alternator plug.

7

Inspect the accessory drive belt and replace with a new one if there are any cracks, tears or glazing to the belt ribs or surface.

8

Route the belt around the accessory pulleys -- all except the tensioner pulley -- according to the diagram you drew, and hold the belt tight so it does not fall away from any of the pulleys.

9

Rotate the tensioner pulley counterclockwise with the 13 mm socket and 2-foot breaker bar. Slide the accessory drive belt under the tensioner pulley and slowly apply tension to the belt. Verify there are no twists in the accessory drive belt.

10

Attach the negative battery cable to the battery and tighten the battery terminal with a wrench. Shut the vehicle hood.