Can A Bad Alternator Cause Overheating

Can A Bad Alternator Cause Overheating

I drove my car with a bad alternator for many years. One day, suddenly my car started to overheat. So, the question that came to my mind was, can a bad alternator cause overheating? So, can a bad alternator cause overheating?

Yes, a bad alternator causes overheating.

I did deep research to find out whether alternators cause the engine to overheat. Finally, I was able to find out how the alternator caused the engine to overheat.

What Does an Alternator Do in A Vehicle?

Alternator of a car

First of all, it is important to understand the alternator. You know that the job of the alternator is to charge the battery and power up electrical components. The alternator directly supplies power to crucial components of the vehicle, such as the ignition and power steering. It generates alternating current (AC). Then that is converted to direct current (DC) by built-in diodes.

What Are the Common Signs of a Bad Alternator?

When discussing the connection between the alternator and overheating, it’s important to identify the signs of a bad alternator. Here are the common signs of a bad alternator.

Low battery power

As I said above, the alternator is the power source for the battery. The battery will not charge properly with a problematic alternator. You will experience difficulties starting the engine. By the time this results in a dead battery.

Dim And Flickering Headlights

When the engine is off, the headlights are powered by the battery. You know it. The alternator supplies power to the headlights when the engine is on. With a malfunctioning alternator, there is not enough power for the headlights. It results in dim and flickering headlights. This happens especially in the idle state of the engine.

Malfunctioning Dashboard Lights

Dashboard indicator light of a car. Parking light, battery light, gas light and wiper light are illuminating

Dashboard lights use alternator power when the engine is on. So, they start to malfunction with a bad alternator.

Engine Stall

You might be wondering how the alternator causes the engine to stall. I will show you how.

The alternator supplies power to the spark plugs in the ignition system. When the alternator doesn’t provide enough power to the spark plugs, it results in a misfire. So, you know engine stalls are common in misfiring engines.

Strange Noises

You can hear strange noises like whining or grinding. Burning smells are also common with these sounds.

You can bench test the alternator to diagnose current-related problems with the alternator.

What Is Engine Overheating?

Vehicle engines are designed to work in specific temperature ranges. When heat goes above that level, we call it overheating. Heat is generated in the engine combustion process. But it should be dissipated by the cooling system of the engine.

What Are the Signs of Engine Overheating?

You can see the temperature gauges rising, which is the first warning sign of the engine overheating. Other than that, you can see some physical signs, such as steam coming from the engine compartment and unusual smells.

Does Overheating Damage an Engine?

Of course. Overheating damages the bearings, piston rings, and gaskets and increases wear in the engine interior.

What Are the Reasons for Engine Overheating?

Here are the common reasons for engine overheating.

Insufficient coolantLow coolant levels result in inadequate heat absorption and dissipation.
Bad radiator capImproper cooling system pressure is caused by a faulty radiator cap.
Radiator damageCracks or leaks in the radiator core cause coolant loss.
Bad thermostatA malfunctioning thermostat prevents coolant from flowing throughout the engine.
Clogged radiatorAccumulation of debris, dirt, and sediments in the radiator obstructs the coolant passage.
Blown head gasketWhen the head gasket is blown, coolant mixes with engine oil. Then coolant quality reduces.
Faulty radiator fanA faulty radiator fan disturbs proper airflow and cooling.
Broken or leaking water pumpDamaged or leaking water pump disrupts the proper coolant circulation.

 Can A Bad Alternator Cause Overheating?

Let’s move on to our question. Can a bad alternator cause overheating?

Yes, a bad alternator causes overheating due to worn-out bearings. In older vehicles, the alternator ran by a belt connected to the engine crankshaft. In newer vehicles, it is run by the serpentine belt. So, in both systems, the engine has to put some effort to rotate the alternator. So, what would happen if the alternator had worn-out bearings? Then the engine has to put a lot more effort into the alternator. It results in engine overheating.

How Hot Should an Alternator Get?

Do you know, how hot should an alternator get? You should know it as a regular driver.

The temperature of the alternator is an indicator of its performance and health. Generally, it is considered normal for an alternator to reach temperatures between approximately 120°F to 140°F (49°C to 60°C). However, if the alternator reaches 160°F (71°C) or higher, there is a problem with the alternator. You should consult a professional if it is.


Can a car start without an alternator?

Your car will start without an alternator. But it won’t have enough power to drive itself. It could be able to drive for a short distance before running out of power. Your car will develop serious mechanical and electrical problems if you run without an alternator.

Can you charge a lithium battery with a car alternator?

Though you can charge a lithium battery with a car alternator, you also need a device to control the current. If not, the alternator will blow up. You can use a DC-DC charger for this task.

Do I need a new battery after replacing alternator?

The battery does not need to be replaced when the alternator is changed. Although these two parts are interdependent, if one breaks, the other shouldn’t follow. Your battery will become depleted, which is the most frequent issue you will have if your alternator breaks out.

Why would alternator fuse blown?

There are several reasons why alternator fuses blow up. They are excessive current flow, a problem associated with the alternator, and a malfunctioning voltage regulator. When the alternator fuse is blown, the alternator stops working. It results in various problems, such as dead batteries and dim lights.


Again, can a bad alternator cause overheating? Yes, it can. So, you should repair or replace the alternator to solve the problem. You can increase the alternator’s lifespan with proper maintenance. Have a nice day!

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *