Battery terminals corroding

Nov 03, 2004 7 Replies

Hi;



On my 99 9-3 the battery terminals are always making a foam like mushroom that is really corrosive.



I had the positive cable replaced once by the dealer, who said that this was a problem with the 99 9-3s, but now its doing it again, right before winter.



Any clue what can cause this? If the battery cables get corroded, then the startup power draw will kill them and the car will not start in the coldest days of the winter.



Thanks for help and ideas!



Cheers, Ben



Grease the battery terminals thoroughly - that will stop the electrolytic corrosion. Use whatever grease you have handy, but not copper or graphite filled grease. I use moly grease for most things.

There are conductive greases specifically designed for this purpose. As Grunff says, any grease will do ( I've used Vaseline ), but I've since switched over to Holt's battery grease. Clean the terminals well ( you can rinse them off with water or a water and baking soda solution if you want to get fancy), and apply the grease liberally.

BL

Cheers!

That's what I wanted to do, but I figured it's an "old" way of fixing the problem.

BTW, is ther a reason for the electrolytic corrosion, given that my VW Golf doesn't do it?

Cheers again!

Ben

BL wrote:

And be exceedingly careful with getting any of the waste water on your clothes or any thing you touch with your hands after touching the battery. That stuff eats through your pants in no time.

I like to use the baking soda and water since it neutralizes much of the acid washing off. I then unbolt and clean the terminals with a wire brush and coat the posts and terms with axle grease. It won't corrode again.

Warning: make sure you have your radio code before you disconnect your battery.

Ummm, that would be *non* conductive grease that you wat to use on battery terminals.

-Fred W

There is some spray stuff you can get that will do the same job and is somewhat less messy than just goobering grease on. It leaves a tell-tale red coating on the terminals. Sold everywhere auto parts are.

-Fred W

There are also some oil impregnated washers you can put on the posts before installing the terminals. Sears sells them in the USA for just a couple of $'s at any of their Auto Centers.

Of course, any of these methods requires clean terminals to start with.

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