What to do when your car battery is leaking

Car batteries really are the unsung heroes of our vehicles, silently powering the electronics in our cars, SUVs and 4WDs so we can reach our destinations without having to think about where the power is coming from. In saying that, there comes a time when the trusty battery that has served you so well every time you start the car can cause concern.

One such issue you may discover is a leaking car battery. In this article, we discuss the safety of driving with a leaking battery, how to identify potential leak sources and guide you on how to handle a leaking car battery.

Is it safe to drive with a leaking battery?

First and foremost, safety should always be the top priority when dealing with a leaking car battery. A leaking battery can lead to a host of problems not only for your health but also your car's health, including electrical malfunctions and potentially harmful chemical exposure. In most cases, it is not safe to drive with a leaking battery. Here's why:

A leaking car battery is a potential chemical hazard
Car batteries contain a combination of sulfuric acid and water, which can be highly corrosive. A leaking battery can expose you to these corrosive materials, leading to skin burns or eye damage if not handled with care. Acid is also not great for anything in your engine bay (you already know this if you’ve seen the Alien movies!).

A leaking car battery can cause electrical malfunctions
Battery acid is likely to corrode electrical connections, often causing erratic behaviour in your vehicle's electrical system. This can lead to difficulties in starting the car, flickering lights or even a complete breakdown (of the car, not you).

Leaking batteries can lead to vehicle damage
Battery acid can also harm other components under the hood, like your engine, alternator or starter motor. The longer you drive with a leaking battery, the bigger the potential for costly vehicle damage down the track.

What to do if your car battery is leaking water from the top

If you notice that your car battery is leaking from the top, it's essential to act quickly. A leaking top can be due to many things, but more often than not it’s due to overcharging, which causes excess hydrogen gas and water vapour to escape.

Here's what you should do:

Safety gear: Before anything, be sure to wear protective gear, including gloves and eye protection, to guard against any potential acid exposure.
Turn off the engine: Make sure the engine is off to prevent electrical complications.

Look at the terminals: Take a look around the battery terminals for corrosion or loose connections. Clean them if necessary and ensure a snug fit. (If you find corrosion, take a look at our article What to do if your car battery is corroded.)

Inspect the battery case: Check the battery case for any cracks or signs of damage. If you see any, that’s usually a clear sign that the battery needs replacement.

Ensure adequate ventilation: If the leaking is due to overcharging, ensure proper ventilation in the battery compartment to disperse any hydrogen gas. This can be achieved by opening the hood and letting the area air out for at least 15-20 mins.

Consult a professional: If you're unsure about the cause or how to proceed, it's best to consult a professional to avoid further damage.

Car battery leaking from the bottom

If a car battery is leaking from the bottom, this situation is a little more concerning. A leak from the bottom can be a sign there’s a breach in the battery casing, leading to acid seepage. Here's what you should do:

  • Remember – safety first: Prioritise safety as always. Wear protective gear and ensure the engine is off.
  • Avoid touching any leaked material: Do not touch any leaked acid with your bare hands, as it is very hazardous.
  • Neutralise the acid: If any leaked acid has come into contact with your vehicle or the ground, it is important to neutralise it. You can do this by mixing baking soda with water to create a solution and carefully applying it to the affected areas.
  • Inspect your battery: Take a good look around the battery for any visible damage to the casing, such as cracks or holes. If damage is present, the battery should definitely be replaced.
  • Get professional help: If the damage is extensive or you are unsure about how to proceed, consult a professional (like us) for further assistance.

How to fix a leaking car battery

Fixing a leaking car battery is not recommended as a DIY task. Whilst it’s important to address the issue promptly, the best approach is to consult a qualified mechanic or battery expert like Allstar Batteries.

We have the expertise and equipment to handle battery leaks safely and effectively. In most cases, a leaking battery will need to be replaced rather than repaired.

Does a leaking car battery need to be replaced?

The general rule of thumb for a leaking car battery is that it should be replaced, not repaired. Battery acid leaks can lead to damage and a range of safety concerns for your car, making it impractical to attempt repairs.

A leaking car battery is a serious concern that shouldn’t be taken lightly. Your safety and the integrity of your vehicle could be in jeopardy if you don’t have the issue seen to ASAP.

If you suspect a leak, always prioritise your safety, turn off the engine and consult a professional to address the issue promptly.

We have the northside of Brisbane covered when it comes to your battery requirements so drop into one of our main stores at Brendale, Caboolture or North Lakes.


12 Garret Street
Brendale Qld 4500
Ph: 0413 692 236


6/106 Lear Jet Drive
Caboolture Qld 4510
Ph: (07) 5309 4905


12/88 Flinders Pde
North Lakes Qld 4509
Ph: (07) 3048 2293


Allstar Batteries - 'Positively the Best'