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I Think My Alternator is Faulty – Now What?

March 26, 2019 3 min read

The alternator is an essential part of your car’s engine. It converts physical energy into electrical energy. This causes the engine to start and powers it so that the car can move.

Alternator problems are indicated by the battery light illuminating on the dashboard, dimmer lights, whining or grinding noises, or the smell of burning rubber. If you suspect that your alternator is not fully functional, take your car to a mechanic.

What steps will the mechanic follow?

  1. A computerized test of the car’s charging systems

This is a test designed to find out if the electrical charging system is weak or not at all functional. Part of the test is designed to establish if any of the alternator’s diodes have failed.

  1. Further investigation

If your car fails the test, the mechanic needs to do further inspections to find out where the problem lies. It could be the alternator but there are other parts that could cause the problem.

  1. Testing the alternator output

Using a multimeter, a mechanic can determine the alternator’s electrical output. The test takes place in two phases: one with the car switched off and the other with the car running. The voltage output should be higher when the engine is running. The alternator is a source of electrical energy in the car, so the voltage should increase when the alternator is engaged. If there is no rise in voltage output, it’s likely that the alternator is not working.

A faulty alternator – what is the way forward?

Once you’re certain there is a problem with your alternator, you have two choices. You can replace the alternator with a new one. Alternatively, you can use a rebuilt alternator. The former is expensive, especially if you buy original parts from a dealership. Together with the mechanic’s labor charges, the cost can be crippling.

A rebuilt alternator is a much cheaper solution. Your mechanic will send your alternator to an alternator rebuilding shop. It takes a bit longer as the mechanic must wait for the alternator to be rebuilt before installing it. However, the cost of rebuilding is far less than buying a new alternator.

Alternator rebuilding is a task best left to the experts. If you feel you would be successful on your own, you can order an alternator rebuild kit from your nearest auto-parts shop or online.

Work smart

Removing the alternator allows you access to the serpentine belt that powers the alternator. Replace it while you have the alternator out. A replacement won’t cost you much. If you wait until the belt is too damaged to function, you’ll have to remove the alternator again to get to it. You’ll wind up paying double labor fees to your mechanic.

Look after your alternator

Most alternators don’t give trouble until they’ve been in the car for at least 10 years. Avoid unnecessary damage to the alternator by following some simple steps:

  1. Make sure all the protective plates, sheets, and shields in the engine are intact and in place. They protect the alternator from unnecessary exposure to the elements such as water.
  2. Make sure there are no leaks in the engine. Oil and coolant leaks can cause damage to an alternator.
  3. Protect your alternator from water and detergent during engine cleaning.