How to Change an Alternator in a 2003 Chevy Malibuby Christian Killian; Updated November 07, 2017
Items you will need
3/8-inch drive ratchet
If the alternator on your 2003 Chevy Malibu is making noise or not keeping the battery charged like it should, it is time to remove it from the car and have it bench tested. If the alternator is no longer working, you can replace it with a new or rebuilt alternator from any auto parts store or a Chevy dealership. There are also quality, used alternators available from salvage yards if you are working on a tight budget.
Locate the negative battery cable on the negative terminal on the battery. Use a wrench to remove the retaining bolt and then remove the battery cable end from the negative terminal.
Locate the automatic belt tensioner on the front of the engine just below the alternator. Insert a 3/8-inch drive ratchet into the hole on the front of the tensioner and rotate it counterclockwise, allowing the belt to slack. Remove the belt from the alternator pulley.
Locate the three mounting bolts that secure the alternator to the mounting bracket on the engine. Remove the bolts with a socket and ratchet, then lift the alternator off the engine far enough to access the wires on the back of the alternator.
Disconnect the plug-in connector from the top of the alternator, pushing in the locking tab and then pulling the connector loose. Loosen the nut on the second connector with a wrench, then remove the nut and wire from the alternator. Remove the alternator from the engine compartment.
Position the new alternator in the engine compartment so it is sitting on the mounting bracket. Install the plug-in connector on the top of the alternator, pushing it in until it locks onto the connector. Install the large wire onto the stud terminal or “b” terminal, followed by the retaining nut. Tighten the nut with a wrench.
Install the three mounting bolts through the alternator and thread them into the mounting bracket. Tighten the bolts with a socket and ratchet, then torque the bolts to 37 pounds-feet with a torque wrench.
Slide the serpentine belt onto the alternator pulley while holding the belt tensioner off the belt. Rotate the tensioner clockwise with a 3/8-inch drive ratchet, allowing it to tighten the belt.
Install the negative battery cable on to the negative battery terminal and tighten the retaining bolt with a wrench.
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