Alternators are not scheduled maintenance items. In other words, you replace it whenever it fails. The charging light on the instrument panel will come on sometimes to indicate a possible alternator failure. Besides that, there really is no way to tell when a failure may occur. If the light does come on, fix the problem as soon as possible because the car won’t run without the alternator. Proper belt tension and serviceability will help extend the life of your alternator. High powered aftermarket stereo systems and accessories can shorten the life of your alternator. A typical alternator will last 6-12 years or 100,000-150,000 miles. A ratchet set, screwdrivers, multimeter, and belt tension gauge will be needed to perform this job. This job can be performed with basic mechanical skills.
Raise the hood. Use multimeter to check the battery voltage at the terminals. It should read a minimum of 11.5-12 VDC. Start the engine and check the voltage at the terminals again. It should be approximately 2VDC higher than the voltage was with car off. This is the alternator output voltage. If the voltage is not correct, troubleshoot the battery and charging system. Check the belt with a tension gauge for 125 lbs. +/- 25 lbs. of tension. Look for any signs of damage to the belt to include: cracks, breaks, fraying, deterioration, and slippage. The belt should be replaced if any signs of damage are discovered.
It is a good idea to take notes and pictures throughout the process to avoid confusion during installation. This is especially true for the belt routing. Raise the hood and disconnect the battery. Jack the right front side of the vehicle and remove the right front side lower splash guard. Remove the right front wheel for more space, but it is not necessary. Loosen the top alternator adjuster bolt. From beneath the vehicle, loosen the lower alternator mount bolt nut. This will allow the alternator to move freely. Push it towards the engine to loosen the belt. Remove the belt from the alternator pulley only. This will help maintain the belt routing for easier installation. If you plan on replacing the belt, remove it completely from all of the pulleys. Disconnect the alternator electrical connections and remove the bolts that were previously loosened. Remove the alternator from the vehicle.
Position the alternator in place and loosely install the bolts. Install the belt and push the alternator away from the engine to tighten it. Tighten the top adjuster bolt enough to keep the alternator from moving. Check the belt tension. Repeat this process until the tension is correct and tighten the two bolts. Connect the electrical connections.