Car Battery Leaking: Why & How To Fix

Although car battery leaks are rare compared to other vehicle issues, it isn’t surprising if you encounter a battery leakage. Extremely cold weather, overcharging batteries, and corroded terminals can lead to battery leaks. But the problem isn’t restricted to these common causes.

Several reasons contribute to a leaking battery. But regardless of the culprit, you must fix this issue as soon as possible. 

Because vehicle batteries store a highly toxic chemical mixture containing sulfuric acid, you must take action immediately. Overlooking this problem may lead to significant issues, risking your life and car’s performance. 

Common Reasons For a Leaking Car Battery 

Knowing the common reasons for a leaking battery keeps you from running into such problems in the future. Besides, finding the cause of this potentially dangerous issue is crucial.

Here are some reasons why your car battery is acting up.  

Old Car Battery 

Car batteries have an extended lifetime. But that doesn’t mean they’ll last forever. An average car battery survives for 3-5 years. 

Nonetheless, a few factors impact its average life expectancy. 

Using the same car battery for a long time consumes all the battery chemicals. Consequently, the battery gets weak and doesn’t provide optimal power to the vehicle. 

So, a worn-out battery might be causing the leaks and needs instant replacement. 

Extremely Cold Weather 

When the temperature drops significantly, the car battery fluids may freeze. As a result, the battery casing expands, and you may encounter cracks in the case. Once this happens, the car battery will start leaking. 

So, if your area experiences ice-cold weather, you need to check if it’s causing the battery leaks. 

We recommend keeping your vehicle in a warm garage instead of parking it outdoors in the snow. 

Overfilled Battery Chambers

The car battery needs a refill time and again to function correctly. So while maintaining it is essential for optimal operation, overfilling the chamber isn’t the way to go. 

Refilling the battery more than the required amount will overflow it, causing spills. 

Battery Cracks 

A leaking battery is inevitable in the event of battery cracks. 

Your car battery contains a mixture of chemicals. As soon as the battery breaks, it’ll leak the acid into the car. Several reasons can cause battery cracks: 

  • Severe weather. As stated earlier, cold weather isn’t suitable for your car battery. The same goes for blazing heat. Blistering summers can also lead to battery creaks. 
  • Bumpy areas. Driving your car in excessively uneven areas might crack the battery. Therefore, you must be careful when driving on rough roads to prevent battery leaks. 


Overcharging any gadget is terrible for its performance; the same goes for your car battery. An overcharged alternator generates a charge more than usual, overcharging your car. 

Consequently, your car battery leaks and might burst in the worst-case scenarios. Experts advise not to overcharge any battery, whether new or old. 

You can always use a smart battery charger to avoid overcharging your vehicle. These chargers automatically stop after charging the battery to an optimal level. 


Your battery is probably overused if you’ve used your car for years and haven’t considered replacements. Over time, the car battery uses all its chemicals. Consequently, it fails to provide enough power to the engine and leads to leaks.  


Sulfation refers to the formation of sulfate crystals on your battery’s surface. This can boil the acid, overflowing the sulfuric solution out of the battery. 

When the solution doesn’t find a place to spill out, the battery might crack, leading to leaks. 

The Battery Tipped Over

A chemical reaction in your car battery produces hydrogen gas. This explains why the battery chambers aren’t fully sealed because the gas needs to discharge. 

If the battery isn’t installed properly, it may tip over, spilling the electrolyte solution. When left unchecked for long, your car’s battery efficiency drops significantly, causing leaks. 

How to Spot a Battery Leakage? 

Many car owners question how to spot a leaking battery. Fortunately, you do not need to call a professional to identify car leaks. Instead, you can check it yourself with a few obvious signs. 

Rotten Egg Smell 

A healthy car with an efficient engine does not produce any smell. Your vehicle should be odorless as you sit inside it. However, if your interior smells bad, it’s a red flag. 

A leaking car battery will typically make your vehicle smell like a rotten egg. So, if you spot such a smell, you must immediately check your car’s battery. 

Wet Battery 

Note that your vehicle’s battery should be completely dry. If you spot a wet battery, it signifies an underlying issue. 

A sweating battery might be leaking because of spilled over acid. Avoid overlooking the battery leaks at this point and get immediate help. 

Corroded Battery Terminals 

Corroding battery terminals is an obvious sign of battery leaks. Make sure you check your battery carefully because corrosion leaks the acids, and touching them can be deleterious to your health. 

Consider wearing protective gloves before observing your car battery. 

Swollen Battery Casing 

The battery casing fits right to pack your battery and keep it safe. If you noticed a bloated battery cover after opening the hood, your car battery is probably leaking.

A warped battery case signifies an underlying problem – think expanded battery fluid due to cold weather. 

Battery Fluid Goes Down Quickly 

Maintenance is crucial to ensure your car’s performance. One way to keep your vehicle working efficiently is to add fluid to the battery. S

o, your battery’s fluid is bound to go down. However, the fluid dropping too often can lead to acid leaks. 


Bubbling is generally seen on the battery’s cell caps. 

Bubbles around the cell caps indicate battery leaks. The seals on a battery might be the source. Make sure you fix your battery to avoid bubbling and annoying car leaks. 

old car batteries

Is a Leaking Battery Dangerous?

Because a few drivers procrastinate on fixing a leaking battery, answering this question is crucial.

A leaking car battery is quite dangerous. Because the car battery contents are acidic, they can damage other vehicle parts. Besides, the corrosive acid can irritate the skin and cause metallic corrosion. 

Also, the hydrogen gas of the battery is highly combustible, and an excessive gas collection can risk your life and your car’s performance. 

Therefore, ignoring obvious car leak signs is not wise. Instead, you must fix minor and major vehicle issues as a responsible car owner. Not only will it keep you from unexpected accidents, but it’ll also keep your car in good health. 

What to Do When a Car Battery Leaks?

Nobody supports the idea of driving with a leaking car battery. Therefore, you must consider immediate fixes by calling in a professional. 

It is always better to hire a mechanic who:

  • Uses quality tools and parts to replace your car battery 
  • Is ASE-certified 
  • Has a good reputation among its past clients 
  • Offers a warranty for their services 

Alternatively, you can tackle the issue yourself. Here’s what you’ll need for a DIY fix: 

  • Sealant 
  • Epsom salt 
  • Plastic bin 
  • Baking soda
  • Sandpaper 

Once you have the equipment, proceed with the fixation process: 

  • Uncover the battery terminal posts and get your hands onto the plastic bin 
  • Now, drain the battery electrolyte into the bin. Be extra cautious at this point because the acidic electrolyte is hazardous for your skin. Do not forget to wear protective gear. 
  • Neutralize the sulfuric acid by adding baking soda into the bin 
  • Empty the fluid in your car battery casing 
  • Sand the creaked battery area using sandpaper until the crack is even and smooth. 
  • Spread the sealant on the cracked surface and let it sit until it dries 
  • Heat 3 cups of distilled water and add Epsom salt to it. Let the solution sit until it cools off
  • Transfer this water into the electrolyte and pour it back into the battery 
  • Wipe the battery dry because excess liquid can corrode the battery 
  • Reattach the battery posts and secure them tightly 
  • Shake the battery for a few minutes and charge it for up to 30 hours

That’s it! You’ve successfully fixed your leaking car battery. 

Fixing a Leaking Car Battery: Tips to Remember 

Working around the battery is not safe. 

Therefore, you must show extra caution when handling a leaking battery. Make sure you wear goggles and protective gloves. Besides, wearing a long-sleeve T-shirt and footwear is also recommended. These steps will keep you from dangerous battery ingredients. 

Finally, experts advise fixing a vehicle battery in a ventilated area and keeping water beside you. In case you accidentally come into contact with the battery acid, wash immediately. 

Closing Notes 

Any car issue can impact its performance and risk your life. The same goes for a leaking car battery. It significantly depletes your car’s functioning and makes it smell foul. 

Fortunately, spotting a car battery leak and fixing it is pretty straightforward. If, however, DIYing seems too much of a hassle, consider contacting professionals. 

They know the drill and will take a few minutes to fix the battery leaks. 

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