Auto Repair Blog

Published 07:00 AM, Tue December 15, 2015

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How to clean a car battery

No driver likes to experience a vehicle that won’t start. Unfortunately, this is something that most drivers will experience sooner or later.

Hopefully you know how to jump the car and bring that dead battery back to life—but that still leaves you with an urgent question: What caused the battery to go bad in the first place?

There are many potential causes for a car that won’t start, and all of them have unique remedies. Here’s one that many drivers never consider, though: Sometimes, the problem is simply that the battery needs to be cleaned.

More specifically, the positive and negative terminals can become crusty and corroded. This causes problems when you try to start your engine, but, thankfully, these problems are not insurmountable.

Cleaning Buildup Off Your Terminals

Here’s how to tackle this problem:

First, turn off your engine. Though this is a relatively simple DIY project, there is still a risk of injury, which simply turning off the engine can help you minimize.

Loosen the nut holding your negative cable in place; you’ll likely need a wrench for this. Unattach the cable from the post, then do the exact same thing with the positive cable.

Once you’ve got the cables undone, it’s a good time to step back and inspect your battery. Do you see any cracks in it that could be causing leaks? If so, it’s time to take the battery to a mechanic and have it replaced.

Next, look at the cables and clamps themselves, and see if you can spot any big rips or tears. Such things can’t really be mended, so if you see these issues you’ll need to have the parts replaced. Next, mix a tablespoon of baking soda into one cup of water.

Mix thoroughly, then dip an old toothbrush into the mixture. Use this to scrub the buildup you see on the battery. Hopefully, you can scour off most of the corrosion you observe.

You may have to soak your toothbrush in the baking soda mixture a couple of times as you keep scrubbing away. When you finish, use a spray bottle with cool water to rinse off any residue. It is imperative to make sure all baking soda and corrosion is washed away before you dry the battery and clamps with a towel or dry rag.

Use petroleum jelly to lubricate the terminals just a bit.
Reattach the cables to their correct terminals.

Note: An alternate, “emergency” cleaning method is to pour Coca-Cola or Pepsi over the terminals, let it sit for a couple of minutes, and then rinse clean with water. You’ll want to follow the same steps of turning off the engine and removing the cables before you attempt this.

Now, this may not fix the problem, in which case you may be due for a new battery anyway. If a visual inspection of your battery turns up some signs of corrosion, though, then this is a cleanup effort well worth making.