6 Symptoms of a Bad Alternator (and Replacement Cost)

Alternators are mechanical devices that leverage the mechanical energy of the engine to charge batteries. The battery powers all the electrical components of the vehicle. The alternator must be in good working conditions at any point. Every driver should be aware of alternator repair and replacement costs. Understanding how the alternator works are vital for identifying defects or failures that may affect its performance. What are some common signs of a bad alternator? How can drivers resolve alternator defects?

Dead battery

When the vehicle is running, the alternator charges the car battery. It also supplies alternating current, which runs the electrical systems. The battery delivers the initial power for cranking and starting the car. Difficulty starting the vehicle may occur due to a dead battery. It means that the alternator does not charge the battery when the engine is running. Although this is one symptom of a damaged alternator, other issues prevent the car from starting.

Failing electrical accessories

Cars have several electrical accessories to complement their functionality. Power windows, air conditioners, stereo systems, headlights and heated seats all draw power from the alternator when the engine is running. The alternator could be bad if these systems fail when the engine is running at low RPM. The failure of electrical components may extend to the dashboard and cause seizure of gauges. When this happens, stop the vehicle and seek professional help.

Growling noises from the engine compartment

Alternators are mechanical components that contain bearings. Restricted movement of these components results in the generation of unpleasant noises within the engine compartment. The rotor may equally seize, and drivers will hear grinding noises. Every driver should take note of the intensity and type of noise to facilitate the accurate diagnosis of alternator problems.

The sudden appearance of warning lights on the dashboard

A bad alternator cannot supply sufficient power for the electronic units of the car. It results in an erratic performance of the electronic control unit. It causes a communication breakdown, and the system displays multiple warning signals. The driver may notice a sudden appearance of a check engine, battery lights or ALT on the dashboard.

Burning smell

An alternator is an electrical device, and any interference to its internal components causes a burning smell. If the rubbing of these components persists, it can escalate and cause fires. The burning smell is an indicator of underlying alternator damage.

Stalling car engine

Modern vehicles rely on electronic sensors for their operation. A bad alternator is incapable of supplying enough power to facilitate the proper operation of fuel injectors. Poor supply of fuel to the combustion chamber impedes the smooth running of the engine.

Alternator Repair and replacement cost

There are two remedies for bad alternators. Repair or replace them. Drivers can perform part repairs individually. Self-repair is possible if the driver has appropriate alternator repair kits. The kit could cost between $20 and $50. Replacement parts are available in local shops at varying prices.

It is advisable to replace damaged alternators where rebuilding or repair is untenable. The cost of an aftermarket alternator falls between $150 and $300. The price could be as high as $1000 when dealing with high-end vehicles. Labor costs for replacement cost approximately $200-$600.

Concluding remarks

Driving with a perfectly working alternator is non-negotiable. Alternators have impressive service lives and last between 5 and 8 years. Watch out for signs of alternator failure and address them at the earliest opportunity possible.


Can I drive with a faulty alternator?

Driving with a bad alternator is risky. There are isolated cases where one can maneuver with a bad alternator. If the vehicle doesn’t stall, one can drive for short distances, say visiting a repair shop.

How long does an alternator last?

The lifespan of an alternator depends on different factors. The components of an alternator may fail at an earlier date. Most alternators last for up to 120,000 miles or 5-8 years of driving.