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Spontaneous Shut off

My wife has a 1999 V6 Mustang that has, all things considered, been remarkably reliable (more reliable than some Toyotas I’ve owned in fact).

However, today the power went off momentarily while we were driving, and then at a red light it shut down entirely. A few moments later it did restart, although neither one of us had done anything other than try the ignition again. I checked under the hood and the terminals on the battery cables were covered in green corrosion gunk. I think the terminals may need to be replaced and possibly the cables. However, I’d like to hear what the community has to say because automotive maintinance is not my strong suit, and I might be missing something that might be not so obvious (or something that me be very obvious, as I said, this isn’t my strong suit).

In the mean time my wife has cleaned the terminals with the usual Sodium Bicarbonate mix. I’ll try to post a picture to give everyone an idea of the level of gunk.

You need to replace the battery and cables.

With that much corrosion, the battery has a major leak at the negative battery post.


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I agree with Tester above. In addition, when you get a new battery, I would apply some dielectric grease to the positive and negative terminals as well. That will help keep corrosion out.

I can’t read the blue sticker clearly, but it looks like your battery might still be under warranty. Check that out.

Thanks for the help.

Testor & Bravesfan314,

Thanks for the help, but that’s not a leak, that’s the result of me taking a picture after my wife dumped the Sodium Bicarbonate solution on the terminal. However, the battery is 3 years old, so it might be due for a replacement.

I agree. But tell me again, your wife cleaned the battery terminals? We had a guy who’s wife loaded fire wood and now one that cleans battery cables? What am I doing wrong? Gotta go unload the dishwasher.

Do you have a post-cleaning (no pun intended) picture?


If you look at the positive battery post, it has one of those red felt washers that’s suppose to prevent that type of corrosion.

It appears that that’s no longer working.

Which means the positive battery post is also leaking.


I got a battery for my wifes car with corrosion buildup, Autozone free installation and the guy cleaned the heck out of the battery terminal connectors, If you you the outside, not the inside of the terminal connector, it may help appearance but do little for the actual connection.

I’ll try to post one in the morning, but it’s dark now.

It helps that I am bad at almost everything. It’s a sad life. Now, I need to go load the dishwasher.

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If the problem continues w known good battery and cables, the ignition switch should be a suspect. Try driving with just a single key in the ignition rather than a dangling chain of keys. If that helps, you’re probably going to have to replace the ignition switch.

As promised, here is the post-cleaning picture.

The little felt-like washer ribbons are the same ones as before, they cleaned up remarkably well just from having the sodium bicarbonate solution dumped on them.

I intend on taking it in to a local mechanic on Monday (It would have been today but they were too busy), in part because my beloved wife pointed out it’s overdue for a tune-up (which might be the root cause). I’ll try and post an update after that future generations of mustang owners can know what to do when this sort of thing comes up.

It may be my eyes . . . but it looks like the terminals may not be completely tight on the posts

What I’ve found is that those felt pads actually PREVENT you from being able to properly push the terminals all the way down on the post, so that you can get a nice and tight connection

A simple test . . . try to wiggle the terminals on the post. If you’re able to do so, you’ve literally got a loose connection

ummm, then don’t look very clean. I’d clean all that gunk off, take off the connectors and clean the mating surfaces.