Blog Car Care Advice Why Is My Car Battery Leaking? (Causes, Solutions, FAQs)
Car Care Advice

Why Is My Car Battery Leaking? (Causes, Solutions, FAQs)

Looking for a mechanic near you for maintenance or repair? AutoNation Mobile Service brings the shop to you. Get a free instant quote today.
Get a Quote

If your car battery is leaking, you’re going to have to do something about it ASAP.

But, what causes car battery leaking in the first place?

And more importantly, what can you do about it? 

In this article, we’ll answer those questions, point you to an easy solution for car battery fixes, and go over some FAQs.

This Article Contains

Let’s get to it. 

Why Is My Car Battery Leaking?

The first thing you should know is that car battery leaks are rare. 

They usually only happen if your battery is very old or has taken some form of damage.  

With that said, here are some common reasons for a battery leak:  

1. An Overcharged Battery

Battery overcharge is one of the more common reasons for battery leakage. 

When this happens, the electrolyte in the battery boils, causing acidic steam to flow out of the vent caps. The steam pools on the surface of the battery, making the unit look like it’s sweating. 

The acid then contaminates the battery’s metal parts, causing battery corrosion. 

This is also one of the easiest ways for your battery terminal to turn rusty.

In more extreme cases, the gases in the battery can build up and even cause it to burst. 

What causes overcharging?

It’s usually the result of a malfunctioning alternator in the charging system of the car.

Smart battery chargers, which will detect when the battery is at full capacity, can help avoid this from happening.

2. It’s An Old Battery

The longer a car battery is used, the less reliable it becomes and the more prone it is to leakage. Car batteries typically last around 4 years on average, though the lithium battery in hybrid vehicles is designed to last longer. 

3. Overfilled Battery Chambers

Unless your car battery is a maintenance-free battery, it will need a distilled water refill every now and then. Unfortunately, overfilling a battery cell with this water can cause it to overflow and spill.   

4. A Cracked Battery

Cracks in the battery can develop if there is excessive shaking or if the battery is not secured correctly in its loose brackets. The chemical reaction in the battery can also cause it to bloat, developing cracks, out of which the electrolyte solution can seep through. 

5. The Battery Was Tipped

The chemical reaction inside your battery produces some hydrogen gas that needs to be vented out. It’s one of the reasons why your lead acid battery chambers can’t be fully sealed.  

If the battery is mounted at an angle or accidentally tipped over, the electrolyte solution inside will spill over each battery cell and possibly out of the vent cap. If left in this condition, the battery cells can dry out and short, reducing your battery’s lifespan and efficiency.

6. Battery Plate Expansion

Hot engine temperatures or overcharging can create excessive heat that expands your battery plates. While this rarely happens, the electrolyte solution in the battery can get pushed out, as a result, causing leaks.

7. Exposure To Extreme Cold Weather

The battery fluid can freeze when exposed to frigid temperatures, creating enough pressure on each battery cell to push the battery casing outwards. The body of the battery can then crack, eventually leading to leaks.

8. Sulfation

Sulfation is when lead sulfate crystals form on the surface of battery plates. Excessive sulfation can increase the possibility of acid boiling over, spilling the sulfuric acid solution out of the battery.

Is A Leaking Car Battery Dangerous?

Yes, it’s dangerous. 

The content of a car battery is acidic. 

And because acid is corrosive, it can damage clothing, irritate the skin, and cause metallic corrosion if left uncleaned. 

The hydrogen gas produced in the battery is also volatile and highly flammable. Any excessive buildup of it puts the life of you and your car at risk. 

What Should I Do If My Car Battery Leaks?

Don’t touch the contents of a leaking battery, and plan to replace it ASAP

If your car doesn’t start, don’t rush for the jumper cables to jump-start it while there’s a leak. Sparks could ignite the volatile gases escaping from the battery and cause an explosion.

So, what’s an easy way to get this problem fixed?

An Easy Solution For Car Battery Leaks

Keeping a damaged battery in your car is not only dangerous for your vehicle but also presents a potential health hazard to you. 

Your safest option is to get that battery replaced as soon as possible. Since driving with a bad battery isn’t advisable, you should get a mechanic to come to you instead. 

To help with your car battery replacement, make sure you find a mechanic that is:  

The good news is that AutoNation Mobile Service meets all those requirements and more!

AutoNation Mobile Service is a convenient mobile vehicle repair and maintenance solution. 

Here’s why you’ll want them to deal with your battery maintenance and repairs:

Curious to know how much a new battery replacement will cost?

That will depend on the make and model of your vehicle, as well as where the repairs take place. A Honda Civic battery change averages around $198, while one for a Ford Escape averages at $220. 

For an accurate estimate of your battery replacement costs, fill this online form.

Now that you know what causes a car battery leak and how to get it fixed, let’s go over some related FAQs.

7 FAQs On Car Battery Leaks

Here are some answers to questions you may have about a car battery leak.

1. What Are The Symptoms Of A Leaking Car Battery?

The symptoms that usually accompany a leaking car battery include:

If your car battery displays any of the telltale signs above, it’s probably damaged and should be replaced.

2. What Kind Of Fluid Is My Car Battery Leaking?

Your car’s lead-acid battery contains a solution of sulfuric acid in water. 

So if there’s a leak, is your car battery leaking acid?

It almost definitely is! 

The only time it’s not acid is if it’s an overflow of distilled water from overfilling.

3. What Should I Do If I Touch The Contents Of A Leaking Car Battery?

If you accidentally touch battery acid, wash your skin immediately with cold water. 

If it gets into your eyes for any reason, flush thoroughly with water and get immediate medical attention.

For these reasons, it’s much better to let a mechanic deal with a car battery leakage and avoid handling it yourself.

4. How Do I Clean Corroded Battery Terminals?

Car battery corrosion is almost unavoidable the older your battery gets. A corroded battery terminal will have less electrical connectivity with the battery cable connectors, reducing its efficiency. 

To help extend the life and performance of your car battery, it’s essential to remove any terminal corrosion that forms.

While this is something you can do yourself, it’s better to get a mechanic to do this for you, as you should ideally remove the battery from the vehicle before cleaning off any corrosion.

Here’s a breakdown of what your mechanic will do 

5. How Do I Dispose Of A Leaking Car Battery?

The workshop that handles your new battery replacement can help dispose of the old battery. Alternatively, you can contact your local recycling center for help. Other workshops will likely be willing to help dispose of the old, damaged, or dead battery, too, for a fee. 

However, under no circumstance should you throw your damaged battery in the garbage bin.

6. Why Can’t I Throw A Dead Car Battery In The Trash?

Lead and acid are hazardous to wildlife and the environment. 

The lead-acid battery was defined as toxic waste by the United States Environmental Protection Agency in 1985. Unless you want to be penalized with a hefty fine, dispose of your dead battery conscientiously. 

FYI: Even household batteries like a lithium battery or alkaline battery (which contains potassium hydroxide) shouldn’t be thrown in the trash because of their chemical composition. 

7. What Are Maintenance-Free Battery Units?

Maintenance-free batteries are sealed battery units that have a slightly different chemistry makeup. They consume less water than older types of batteries and don’t need periodic refills with distilled water. 

However, they’re not free from fault. 

They can get damaged and develop leakage, and often have a set life cycle, after which they’ll need to be replaced.

Closing Thoughts 

A leak from your car’s battery (or from any battery pack, for that matter) is always a cause for concern. Be mindful that some batteries can contain hazardous materials — like sulfuric acid, and need to be dealt with professionally.

Fortunately, to get your car battery replaced safely, rely on AutoNation Mobile Service.

Contact them, and their ASE-certified mechanics will be knocking at your door, ready to fix your leaking car batteries!