How do I know if my alternator needs replacing?

The functions of an alternator.

The alternator is an essential piece in your car. It powers the vehicle’s electrical system, from the on-board computer to the seat warmers to the radio. It also keeps the battery charged.

A conventional alternator is driven by a serpentine (drive) belt that turns faster than the engine. It makes millions of revolutions and can wear out with time.

In hybrid and electric cars, as well as those with idle stop-start technology, the alternator also acts as a starter (reversible alternator). Here, it’s powered by the batteries instead of a belt.

Without a functioning alternator, your car would stop working after the battery charge is depleted.

What are the signs indicating a faulty alternator?

One sign that your alternator is faulty is if the car battery warning light on your dashboard stays lit after you start your car. The battery is then not charging correctly. A weakened alternator won’t be able to supply enough power for all of your electrical accessories like the stereo, the heater fan or your onboard computer.

Since the belt turns faster than your engine it wears out over time and can cause failures in the ball bearings, ignition coils, or magnets of the alternator.

If the voltage drops or if the car becomes difficult to start, it means the battery isn’t charged properly and needs an adjustment or a replacement part.

Furthermore, frigid temperatures diminish a car’s battery capacity and prevent it from recharging properly.

The certified technicians at John’s Thistle Auto in Ladner, BC have the expertise to diagnose belt problems, test the battery, or replace the alternator.

How often do you need to maintain your alternator?

The alternator should be inspected and the belt should be replaced at regular intervals as specified by the manufacturer.

Your John’s Thistle technician will test and install an alternator that meets your manufacturer’s specifications.

If you use a lot of additional electrical devices in your car, such as computers, tablets and DVD players, or if you regularly tow a camp trailer with a battery that recharges as you drive, we can upgrade you to a more heavy duty alternator that meets your needs.

Call 604-946-6626 or email or drop by the shop in Ladner at 4892 Elliott Street.