Dear Tom and Ray:
There is a fluffy white/blue deposit at the base of the positive terminal post of my battery. The service manager’s explanation is: This is perfectly normal for a sealed battery. When a battery is charged, gas escapes from a small gap between the post and the battery case and forms the deposit. The service manager recommended “corrosion treatment” for about $20. Are all batteries designed this way? Is this corrosion treatment worth it? – Art
RAY: We see a lot of batteries with a little bit of corrosion at the terminals. But if there’s a lot of buildup there, it could signal a problem.
TOM: Right. Batteries and charging systems that are functioning properly don’t create mountains of whitish-blue crud on battery terminals.
RAY: So you could pay this guy $20 to take care of it for you. Or, if you prefer, you can clean it up yourself. You just mix up a cupful of baking soda and water, to the consistency of watery pancake batter.
TOM: Then slather it all over the terminals. It attacks the corrosion, and then you wash it all off with a hose or a bucket of water.
RAY: We also use a spray you can buy at an auto-parts store that coats the clean terminals and prevents the corrosion from coming back – kind of.
TOM: If there’s something wrong with your battery or charging system, the corrosion will come back despite the spray. So, then you’ll need to investigate.
RAY: The most likely culprit is an alternator that’s overcharging – like we do all the time at the shop – and causing your battery to out-gas.
TOM: So, Art, I’d clean off the terminals, re-secure the connections and then keep an eye on it. And if the stuff comes back in a couple of months, put the 20 bucks you saved toward a complete charging-system check.
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Why do unmitigated cheapskates like Tom continue to buy nothing but old clunkers? Find out by ordering Tom and Ray’s guide “How to Buy a Great Used Car: Secrets Only Your Mechanic Knows.” Send $4.75 (check or money order) to Used Car, P.O. Box 536475, Orlando, FL32853-6475.
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(c) 2008 by Tom and Ray Magliozzi
and Doug Berman Distributed by King Features