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Blue powder around the positive terminal of the battery

edited June 2012 in Repair and Maintenance
I just stopped by a store after work to pick something up. I pulled up and turned off the car. I was gone for about 1 minute. When I got back to the car, it wouldn't start. This has never happened before.

When I popped the hood, there was a bunch of blue powder around the positive terminal of the battery. I cleared most of it away with a cloth while waiting for someone to give me a jump. I got a jump and drove home and turned off the engine. I immediately tried to start the car again and it wouldn't start.

Do I need a new battery? How much do they cost? Can I install it myself? I have a 99 Mazda Protege that I bought second-hand about three years ago.

Mostly I get around by bike, so I am not sure what to do or if I'll be able to afford this.


  • Corrosion around battery cable terminals can be quite common. Cable terminals and battery posts should be cleaned about once a year.

    At a minimum you will need to clean the terminals and battery posts and it's possible that your car might need a new battery. If the battery is 5 or more years old and sits idle a lot then it's questionable.

    Battery cost will vary but a Protege should use a lower end, more inexspenive battery; probably in the 60-75 dollar range.
    I think auto parts stores such as AutoZone will install one for you free and even Wal Mart may do the same.
    They will also test the battery for you free of charge.
  • Blue-green powder is corroded lead from the battery terminal. Acid from the battery leeching out around the top post is causing the corrosion. I'd clean out the corrosion first and get the battery charged and then load tested before condemning it. The best way to clean the corrosion is to brush off the heavy stuff and disconnect the battery terminals. Then use a pasty mix of baking powder and water with a small stiff brush to neutralize and clean off the residual corrosion from both the post and the conncetor. Finally, use a battery brush to get the post and inside the connector clean and shiny. Then reconnect the connectors, positive first, then negative.
  • I had this happen to me last winter. The car was running fine, I pulled in to get some gas, and it wouldn't turn over when I tried to start the car. Plus all the console lights slowly faded out.

    I popped the hood and found I could twist the battery cable. It had worked itself loose probably from thermal expansion/contraction due to heating and cooling. I tighted it up and the car started ok. Later I took off both cables, cleaned up the connetions. Anybody can do this, but you need a special $1 terminal cleaning tool from Harbor or any car parts store.

    Sears auto (at least they used to do this) has a free service where they'll check your battey. No charge -- no pun intended! Seriously, they'll recharge it first, then check it with a load test. Then you'll know if you need a new one or not.

    Batteries cost anywhere from $50 to $150 or more. Check Consumer's Reports. They have a battery article once a year or so. The best value battery -- according to CR -- comes from differrent vendors depending on the type of battery your car uses. I've had good luck with CostCo batteries and while a little more expensive, Sears batteries have proved good for me too.
  • Blue-green is typically corroding copper. You're probably OK if you clean the connections as described above. If you want to be sure, several auto parts places will check your battery for free.
  • Remove both battery terminals (wear rubber gloves) and clean the posts and terminals with a baking soda solution A tooth brush, wire brush, special cleaning tool are helpful. See if that does it. If not, have your battery and alternator tested. Most of the chain parts stores will do this for free...If battery replacement is needed, it's less than $100...
  • That blue powder and the fact that your car won't start tells me your battery is probably 4-5 years old, and is probably due for replacement. Many auto parts stores will test your battery for free, and many will even install it without charging for labor. However, auto parts store employees are not mechanics, and you need to check their work to make sure the battery is secured properly. Get your battery tested for free, and I bet you will be buying a new battery soon.
  • Remove and clean your cable ends and clean the posts. Tighten the terminals and give them a coat of petroleum jelly.
  • It's hard to improve on the replies you have already received. However if you decide to disconnect and clean the battery terminals, disconnect the negative terminal first and reconnect it last. If you disconnect the positive first and touch the frame the battery will be shorted. A couple of hundred amps at 12V can weld a wrench to the frame. I did this once with a 69 Buick, I don't like to think what it could do to a new car with its electronic and computers. The following link explains it better than I can.

    In your place, I would clean the terminals and replace the battery if it's more than 3-4 years old. There should be a sticker with the date on the battery.

    Ed B.
  • On the side of thebattery is a small sticker with a letter andnumber on it. the letter is the mounth the battery was made a = Jan. b = Feb. and so on there is no "I" and the number is the year it was made in.
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