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Cleaning battery terminals

'08 Civic; daughter’s car. Needed jump start again today (last time she mentioned it was a couple of months ago; don’t know if there were more occurrences). Records show no battery replacement since we bought the car in 2010. (Hard to believe.)

She went to Advanced Auto Parts, and they said battery is OK, but terminals could use cleaning. She bought some kind of spray, and will be by this evening for me to work my magic.

I have not serviced a battery in about 20 years. With all the computers and other electronics in cars nowadays, am I OK just to disconnect the cables from the terminals, clean it up, and reconnect?

I might have time to run to parts store and get the red and green felt washers. Are they a good idea? Any other advice?

(I feel like an ignoramus, but at least I know enough to ask.)

This is your daughters car and it has a 6 year old battery. Don’t mess around just go to Sams, Costco or even Walmart and put a new battery in. Why take a chance on it failing someplace that might not be as safe as you would want it to be. Even most Auto Zone stores will replace batteries.


Good questions all. Do you have a terminal brush? They’re cheap, good to have:

I’d just disconnect each cable, clean it, then tighten it back on.

But I would replace a 6+ year old battery first.

+1 to the previous responses.
While cleaning the battery terminals is definitely a good thing, in this case it is tantamount to rearranging the deck chairs on The Titanic.
(Translation=It won’t do any harm, but the ship–or in this case, the battery–has a very short life span remaining.)

The OP may be able to get a few more weeks or months of functionality out of this battery, but unless this over-aged battery is replaced in the near-term, his daughter is sure to wind up stranded at some point in the near future when that senior citizen battery dies its inevitable death. Since the cost of replacing that aged battery will not be lower in a few months, I suggest that the OP replace it now in order to save his daughter from the inevitable stranding (and possible towing) when it does die in a few months.


Count me in this chorus. Once a battery goes dead, it needs to be replaced ASAP. Do clean the terminals on the cables. I do think the red and green washers help. I would also use a battery that has removable caps over the cells to add water every coupe of years.

I went to Autozone for my daughters battery, 65 cranking amps on the old one, free install. They used a memory tender and cleaned the heck out of the terminal connectors. Get a new battery and be done with it, you are due. Massive corrosion can be a sign of outgassing, so the battey might still test good but on it’s last legs.

Before disconnecting the battery, whether for cleaning terminals or for replacement, make sure you know the code for the radio. As an anti-theft measure, car radios will not work if they are disconnected from and reconnected to power, until the correct code is keyed in. Hondas come (or did come when mine was new) a hang tag on the radio with a numeric code for that radio. The owners manual will tell you the process for entering the code.

Alternatively, you can buy or make a gizmo that keeps a 9V battery hooked up to the battery cables while they are disconnected. That’s enough the preserve the radio’s and the ECM’s memory for a while, as long as you don’t have a larger current draw happening, such as a dome light.

You may able to get the code from a Honda dealer if you provide the VIN and proof of ownership, and maybe some payment.

After 5 or 6 years I feel a new battery is a reasonable and routine expense, especially if reliability if a top priority, and the old battery is suspect.

Yes, I do suspect a 6-yr-old battery (6 years since we bought the car; 8-ish years since the car was new!). But, as I said, hard to believe my records. When I get to see it this evening I expect to find some labels that tell me how old it is.

Thanks for the reminder about the battery terminal brush. I do have one, a hand-me-down from Dad; must be 50 years old.

And I found a set of the red and green felt washers on my workbench parts shelves. Ready to go!

Before disconnecting the battery, read this first.

Especially what it say’s about disconnecting the battery on some Honda’s.


Get a new battery and go on with life.

I strongly recommend getting a new battery and being sure the shop order defines your wish to have the cable terminals cleaned and anticorrosion coating applied. There are also some anti-corrosion washers available. I haven’t used them, I like the gel (there is also spray), but I understand they work well.

If ever you service a battery yourself, be sure you disconnect the negative (-) cable first and always wear proper eye protection. That prevents a spark and possible explosion of the battery’s hydrogen gas, and prevents blindness if the worst happens. On modern cars, you may want to get either a 9VDC “plug in” backup to keep your computer’s memory intact (be sure the power port you plug it into stays live with the key off) or a power-pack for the same purpose. Otherwise your computers may lose their memories.

I’ve always disconnected the NEGATIVE (-) battery cable first.


Um… I screwed up! I’ve corrected my admittedly stupid mistake. I don’t know why I did this. :flushed:
Thanks Tester.

Thanks for all the good advice. Had I seen Tester’s warning in time, I might not have gone ahead and disconnected the battery. Anyhow, here’s my report:

  • Found the receipt. Battery was bought 8/2012 from Autozone, who also installed it.

  • Top of battery was quite dirty, with a little blue-white corrosion on the hold-down bar.

  • Terminals did not look so bad.

  • The electrolyte level in the three cells on the pos end was fine. The three on the neg end were a tiny bit low. Added distilled water.

  • The spray cleaner my daughter got was some general battery cleaner. “Foam will turn pink if acid is present.” Which it sure did, all over the case of the battery.

  • I cleaned the terminals and connectors with the brush.

  • I put it back together, with the felt washers. It started fine. (Daughter says she has the code to get the radio playing.) So far, no panicky reports of drivability issues. She’ll be back at her place in a bit, and I’ll get a fuller report.

  • She is going to get a new battery anyhow. I suggested that she drop in at Autozone and see if she can get some satisfaction on the 7-yr pro-rated warranty.

Thanks again for the advice.

A tip of the hat to you for a job well done, and a sincere thank you for posting the results. A happy ending is always a good thing to read.

Happy motoring to you and your daughter both.

I usually try to connect jumper cables from another known good battery, in another car, to the positive terminal and the engine block or a good body ground before I disconnect the cables on a newer car. Everything stays happier with a steady 12 volts. Certainly the stereo, but also the computers and the memory in the system that monitors all sorts of emissions. It just seems like good policy.

And Costco keeps records for you, so when you show up with a dead battery they know exactly when you bought it, and they do the math on the warranty. Nice, but sort of spooky.