Can a Car Battery Die While You’re Washing The Engine Bay?

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car battery installed in the vehicle

The engine bay is usually the dirtiest area of the car since many people don’t like cleaning it – it’s mostly because they’re scared of screwing something up. Mostly, people are afraid of damaging the battery. Can a car battery die while you’re washing the engine bay? That’s what I’ll discuss today.

Even though modern cars have covers for all the sensitive areas in engine bays, it would be best if you still disconnected the battery while washing the engine bay. That way, you’re 100% sure that it won’t die during the washing stage.

For those of you looking for a quick answer, you’ve got it above. However, I think that there is additional information you should know, especially for beginners in the auto detailing world, so make sure to read the rest of the article.

Can Your Car Battery Really Die While Washing The Car’s Engine Bay?

Let’s dive a bit more into the question.

As I already said, all the sensitive components in engine bays are protected, at least generation cars from 2000 and above. The same situation is with the battery; you’ll often see a plastic cover over it.

Those covers on sensitive parts are fantastic, and they will protect components from damage during driving and washing, but the car battery is a bit different.

The battery provides some power to the car all the time, which means that it’s never off (unlike most other components), and leaving it unprotected may result in battery drain or, even worse, battery dying. That’s why I recommend disconnecting it while washing the engine bay.

From my experience, even if you never protect the car’s battery, there’s a small chance of it dying. While I was inexperienced, I washed engine bays on my cars without covering or disconnecting the battery, and nothing bad ever happened (except once when the car was working on 3 cylinders for a few mins, but it wasn’t because of the battery).

But again, I may only have had luck with it. Below you can see an example of problematic engine wash – nothing is covered or protected.

leaving the battery connected while washing the engine bay
Check the battery, it’s still connected!

Don’t be the guy in the picture above (Like I used to) and let the battery look like this when washing your car. Always make sure to disconnect it and cover it with a plastic bag.

How To Disconnect The Battery While Washing The Engine Bay?

Disconnecting the battery won’t take more than 2 minutes, and it would be a shame if you don’t do it as a prevention step.

To prevent the battery from dying while washing the engine bay, just disconnect the negative (-) terminal from the battery and put some plastic bag (I use a grocery bag or trash bag) over it.

Also, cover any other electric parts attached to the battery to prevent water from damaging them.

To disconnect the negative cable (the black one) on the battery, in most cars, you’ll need a small wrench (usually 10mm or 12mm), and you’ll have to just loosen the screw a few turns until the cable can be easily disassembled from the battery.

What you can also do is remove the battery completely. Even though it’s not needed, it may give you more space to thoroughly clean an engine bay. However, removing the battery entirely will take you a bit more time, but no longer than 5 minutes, which is still quite quick.

Additional Prevention Steps

Even though disconnecting and covering the battery will keep it safe, there are still some other prevention steps you should ALWAYS take when washing the car’s engine bay.

Additional prevention steps to keep car battery safe while washing the engine bay:

  • If using a high-pressure washer, wash the engine bay from a distance
  • Let the engine bay completely dry before connecting the battery again (you can use an air compressor to speed up the process, even just a quick wipe with a microfiber towel is enough)
  • When using water, make quick passes and don’t spray it in the same spot for more than 1-2 secs (especially around the car’s battery)
  • You can also opt for a waterless wash, which is a great and safe option for cleaning engine bays. Here’s how to wash the engine bay without water.

I Didn’t Disconnect The Battery, and Now The Car Won’t Start – What To Do?

If you didn’t disconnect the battery while washing the engine bay and now your car won’t start, there’s still a chance that nothing extremely bad happened.

Here’s what I would do in your situation:

  1. Disconnect the battery completely, remove it from your vehicle and let it dry. You can also use some brake cleaner or wd40 and clean the connectors (terminals) both on the battery and on the cables. Then, try starting the car again.
  2. If the car won’t start again, you may have to jump-start it. So, make sure to use a jump starter and try starting the car. The car will probably start, and hopefully, the battery only drained.
  3. If the jump-starting method doesn’t work and the engine bay is now completely dry, it may be a problem with a distributor cap and rotor since they’re also pretty sensitive. However, for that, you’ll need a mechanics’ help unless you’re an experienced automotive DIYer.

Final Words

Now you know that car batteries can die while you wash the engine bay, and you also learned how to protect them from dying. Even though it’s rare that the battery will die even if you leave it unprotected, it can still happen. Prevention is the key, and you should always take prevention steps even if there’s the smallest chance of something bad happening.

Let’s wash some engine bays (while keeping the prevention steps in mind)! 🙂

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