A bad odor is the most off-putting sign, be it a person or a vehicle. It indicates that you need to stay away from them. There is nothing more worrisome than a car than reeks with a bad smell. Especially if the car battery smells like rotten eggs when you open the hood, you need to rush to the mechanic.

car battery smells like rotten eggs

Why Does Your Battery Smell Like Rotten Eggs?

The reason that your car is stinking as if someone has smashed rotten eggs all over it is that your car battery is not in a good condition.

When the battery goes bad, the chemicals inside it create hydrogen sulfide gas using sulfuric acid. This gas, known as “sulfur stink” is what causes the rotten eggs, sewer or garlic-like smell when it starts to leak from the broken or cracked car battery case.

Here are the reasons why your battery smells like rotten eggs:

  • The car battery is overcharged, as the excessive currents result in more sulfur gas
  • The battery is dead resulting in gas leak
  • The battery has low electrolyte levels resulting in exposed lead plates (hydrogen gas encounters the sulfates on the lead plates forming hydrogen sulfide)
  • Damaged catalytic converter in the battery resulting in gas leak
  • Vent gas resulting from a frozen or misshapen car battery

How To Get Rid Of Rotten Eggs Smells?

Now that you have located the source of the nasty car battery smell, it is essential that you get rid of it as soon as possible.  It is not just that the smell is unbearable, if left as is, it can endanger the car and your life as well.

You can do many things to get rid of the rotten eggs smell, including:

  • Regular checks and proper maintenance of the car battery alongside each of its components such as cells, wires, electrolyte levels is mandatory.
  • Keep your car safe from rapid fluctuations in the environmental temperatures. Leaving the car in extremely cold weather can lead to a frozen battery whilst excessive heat can result in overcharging and gas leak.
  • Clean of the corrosion, if any. Use vinegar or baking soda on the toothbrush followed by fresh water to rinse off the corrosion from the battery. Dry thoroughly and cover all parts of metal with petroleum jelly. Voila, the car battery is rotten eggs smell free!
  • You have invested so much in your car, just go an extra mile, and get a smart battery charger. It helps to enhance the car battery’s life and functioning by causing desulfation, reconditioning and setting the car battery in the recovery modes, automatically.
  • Get the old or malfunctioning car battery replaced. Ideally, it is recommended to replace the car battery every 3-5 years, but it all depends on the battery life, environmental conditions and your driving habits.

Is It Dangerous To Drive A Car When The Battery Smells Like Rotten Eggs?

The gas causing the rotten egg smell is very dangerous for you, the car and the environment.

Taking the car out for a drive when the smell specifically indicates that there is something wrong with the car battery is not a sane thing to do. If the car battery is not dead yet- which you are not a hundred percent sure off- it soon will be if you plan to take it out on the road.

Hydrogen sulfide- the culprit behind the rotten eggs smell, can cause irritation and inflammation in the eyes, throat, nose and the respiratory system- making it difficult to breathe. Therefore, even if you get a slight whiff of this smell, get your car battery tested immediately by a professional. In addition, meanwhile, stop using the car.

Moreover, when the sulfuric acid, hydrogen or oxygen gas fumes escape into the environment via vents or cracks in the battery, they can result in fire or an explosion if accumulated in a small area.


The smooth and safe function of the car is intertwined with the good health of its battery.

If you encounter the rotten eggs smell, or any other signs that indicate the bad health of your car battery, identify and treat the cause. The best option would be to get a new car battery, especially after the nasty odor that you can still not get out of your mind and nose.

Car Battery Smells Like Rotten Eggs? (Issues and Solutions)

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