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Battery terminal chronic buildup

Sorry if a repost as it appears my first failed. 03 windstar, 4 year old battery, I cleaned the terminals last summer and the pos terminal looks like a chia pet. Sure I can clean it again, but why is it happening?

There’s a battery leak at that post.


Agreed. You can’t fix the leak so clean it regularly until you are ready to replace the battery.

This is called “outgassing”. I fought the same problem for more than a year on my 2011 Toyota Sienna. One thing that helped was that I purchased these red and green impregnated rings that go under the battery clamps. They come with a spray that is supposed to retard the build up of the corrosion on the battery terminals. A couple of weeks ago, I finally gave up. One side of the positive clamp was almost eaten away. I put on new terminals and had the battery load tested. The load test showed that the battery was marginal, so I replaced it.
When I talked to the service personnel at the Toyota dealer, I was told that they had experienced quite a few batteries in Toyotas with this problem. The battery in my Toyota was manufactured by Johnson Controls, but the problem can happen with any battery.

Agreed. The seal around the battery post is broken, allowing acid fumes to seep through causing accelerated corrosion. As Triedaq noted, you can do things to slow down that rapid corrosion, but it has a way of winning in the end.

You can put on the little green and red felt rings on the battery posts under the cable clamps. You can buy them at any parts store for .99 cents. They work great and keep it from corroding.

@knfenimore–the red and green rings work for me for about 9 months to a year. Ultimately, corrosion disintegrates them, particularly the red ring under the positive terminal. This proves that the rings are doing the job–the corrosion is neutralized by the chemicals impregnated in the ring. These rings are cheap enough so that there is nothing lost in using them and replacing them as needed.