4 Alternator Repair FAQs
Here are answers to some common questions on alternator repairs:
1. Can I Drive With Alternator Problems?
Yes, but only for a short while before the battery fails, then you’ll need an alternator repair.
2. How Often Do I Need An Alternator Repair?
An alternator can generally last for about 150,000 miles or 7-8 years before needing replacement.
3. How Do I Load Test An Alternator?
To load test your alternator, you need a voltmeter or multimeter.
Here are the steps to take:
- Battery assessment: With the engine turned off, connect the multimeter leads to the battery terminals — red to the positive terminal, black to the negative terminal. A good, fully charged battery should measure between 12.6 -13.2 volts.
- Alternator assessment: Turn on the engine. With the engine running at around 1000 RPM, the multimeter voltage should stay within 12-14 volts.
- Load engine: Start turning on accessories (like the headlights, radio, and windshield wipers.) The voltage shouldn’t drop under 12V or go above 14V.
If any readings are out of range while the engine is running, your alternator could be problematic, and you may need a car repair.
4. How Do I Replace An Alternator?
Here’s how a professional mechanic would replace a failed alternator:
- Disconnect the negative battery cable.
- Disconnect the cable connections from the back of the alternator.
- Remove the drive belt from the pulley by loosening the belt tensioner.
- Once the belt is off, unfasten the mounting bolts connecting the alternator to the bracket.
- Remove the old alternator from the bracket.
- Compare the new alternator with the old alternator and check whether everything matches, including the mounting bolt holes.
- Install the new alternator and tighten the mounting bolts with a ratchet.
- Slip the drive belt back in position by using the tensioner arm and reinstall all cable connections.
- Review the installation and test the alternator output using a multimeter.
Tips: Ensure the battery is fully charged before installation. Using the new alternator to charge a low volt battery can damage the alternator.