Is Your Battery Light On And Engine Overheating? [Solved]

Is your battery light on and engine overheating? If the drive belt has broken off due to lack of maintenance or poor part quality then this kind of issue can happen.

An instrument cluster lit like a Christmas tree can easily scare anyone. If a person does not has enough knowledge about his car, then it can be a daunting task for him to diagnose such problems. The engine of the car is dependent upon many sub-components and they are run by an accessory drive belt.

What Causes Battery Light On And Engine Overheating?

If the accessory drive belt that, turns your alternator and water pump is broken or failed due to poor part quality then it can cause overheating and the car battery to be on continuously. These problems can be explained in the following ways-

1. A Broken Accessory Belt

If the accessory drive belt that, turns your alternator and water pump is broken or failed due to poor part quality then it can cause overheating and the car battery to be on continuously.

In this case, the water pump and the alternator, do not spin, and this is why the battery light and overheating conditions happen at the same time. This can be very dangerous as the oil temperatures and engine head temperature will rise exponentially and can do a lot of damage to the engine.

2. Failing Car Alternator

A bad alternator, then it won’t sufficiently charge the battery as it is supposed to, while the engine is running, it can cause the charge to deplete faster than usual and can also spike voltage.

High voltage can cause the temperature meter to show an unusually high reading, fooling into thinking that the car is overheating. In some cars, the water pump is electric and a bad alternator will not help it to run efficiently, causing overheating and battery light on the dash. 

3. Stuck Water Pump

A bad water pump can cause the car to overheat as it would not be able to circulate the water properly. Also, a seized water pump will cause very high resistance and as a result of that, the accessory belt will stop spinning.

It will ultimately cause the alternator to not produce enough electricity and as a result that the car battery sign will turn on automatically. Hence a bad water pump can cause the battery light on and engine overheating.

4. ECU Sending Wrong Signals

An ECU of the car is like the brain of the whole car. It controls almost everything in the modern car such as the light bulb and whole fuel injection. A bad brain will cause everything to go haywire and nothing will work properly.

In the case of a bad ECU, the instrument cluster can show false reading and you can experience battery light on and engine overheating.

How To Repair Car Overheating And Charging Issues?

This issue is a simple one and can be easily repaired cheaply. The following ways can be followed to repair the car-

1. Install A New Drive Belt Kit

The accessory drive belt is the major cause of battery light on and engine overheating. The easiest way to solve this problem is to replace the old drive belt itself. The drive belt is general wear and tear item and it can break or fall apart.

But if you are religiously following the manufacturer’s maintenance schedule, then it is highly unlikely that you will not face this kind of issue. It is recommended that you do not drive your car without an accessory belt. It is advised that you should to your car to the nearest mechanic. 

2. Replacing Water Pump

A seized water pump can cause friction in the drive belt, leading to the engine component not running properly. It will also cause overheating. A failed water pump will not circulate water at the proper pressure for what it is designed for.

So, it is recommended that a new water pump should be installed. It is cheap and easy to replace and does not cost much time and effort. 

3. Checking The Car Electricals

The car’s electrical system plays an important role in its proper running. A failed electrical system, due to a bad ECU or a bad alternator can cause several functions. It can show overheating and battery light on the instrument panel at the same time. So to fix the problem, the alternator or ECE can be repaired. Or in the case of some cars that can only be replaced. 

How Dangerous Overheating And Battery Light Issues Can Be?

This situation can be really dangerous as a broken accessory drive belt will not run the essential engine components. As a result, it can cause serious overheating of the engine. It is not are not uncommon where the engine head has even melted and become beyond repairable.

Also, a nonfunctioning alternative will not be able to recharge a car battery and as a result, it will eventually deplete the battery, leaving you stranded.

Can I Drive With A Failed Drive Belt?

It is not at all recommended to drive your car in this condition because the consequences are very grave. But in case of emergency or where you cannot find a proper towing service, then it is recommended that you drive your car at a few miles interval, keeping a hawk’s eye on the temperature meter of the car.

A car with a nonfunctioning alternator will be running on its battery and it is expected that it won’t last more than 30 to 40 minutes.

How Much Will It Cost To Fix Overheating And Electrical Issues?

Since it involves many components, the cost to fix the electrical system and engine overheating is variable. If the drive belt is the cause, then it will cost you around 100-600$. A new ECU or Altenator will cost in the range of 500-1000$. Used parts are also available for a fraction of the cost. The water pump will cost in the range of 300$.


Fixing overheating and battery issues is very simple and can be fixed by your friendly neighborhood garage very easily. If your mechanical knowledge is sound, then you can do this job on a weekend in your driveway itself. If you still have any questions regarding the issue then feel free to comment. 

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