Help assuage my concerns about my little old car!
November 12, 2012 11:19 AM   Subscribe

Please help me determine what happened to my car recently - was it the battery, the alternator, or something else?

A week ago I was driving to work and everything was fine as normal. I had been driving for about five minutes with the heaters, radio, lights etc on.

Suddenly, with no warning (no gradual loss of power, no warning lights) the car lost power totally and utterly. Everything went off, and I couldn't even put the hazard lights on. Attempts to restart the car were unsuccessful, and the radio and lights etc didn't work either.

My husband arranged for it to be towed to a local garage, but not our normal one.

The garage said that the problem was the battery. We had noticed previously that there was quite a bit of corrosion on top of the terminals - what looked like set frothy green stuff - but we'd stupidly neglected to get it checked. My husband thinks that the garage explained that the corrosion was making the battery unable to connect to whatever it connects to (as you can tell, I am incredibly clueless about cars, as is my husband!), and this was what caused the breakdown. They fitted a brand new battery and since having this fitted the car has run fine.

However I am concerned because everyone I have told has said that it sounds much more like the alternator dying than the battery, and people have said that batteries just don't 'die' like that once you've got going - that if it was a battery problem you'd simply be unable to start the car. I am really worried that the garage have not fixed the actual problem, and that if it is a faulty alternator the same thing will happen again. I was lucky it happened when I was only travelling at about 10mph, coming up to some lights - I'm terrified it will happen again when I'm on the motorway or something.

My husband is reluctant to ring up the garage and clarify exactly what the problem was because they did it sort of as a favour because they know his dad. He is also happy to accept their explanation and not anyway near as concerned as I. If I need to we will take it to our local garage to be checked out, but we've already spent £300 on the car recently and I can't afford it unless it's absolutely necessary!

So, if you have any car expertise at all, please could you advise me - does it sound like the battery was the problem and I'm ok and worrying for nothing? Are people correct when they object that batteries never just die like mine did? Do you think it is actually the alternator and the garage fitting a new battery was totally wrong?

The car in question is a 12 year old Ford Fiesta, if it makes any difference.
Thanks in advance!
posted by schmoo to Travel & Transportation (12 answers total)
This problem definitely could have been caused by corrosion in the battery cable - typically the negative battery cable. Check and see if it has a new negative battery cable (the thick cable that runs from the negative battery terminal to the frame or engine block). If it has a new negative cable, and a new battery, and it's now running fine, I'd say the garage did you a solid and fixed the problem.
posted by mosk at 11:26 AM on November 12, 2012

I had the same thing happen to me a number of years back in a mid-nineties Mondeo. The battery had died a week or two before and I'd had it replaced. The car then suffered a couple of brown-outs at motorway speeds (oh! joy!) before finally dying on a normal residential road.

The problem in my case turned out to be the alternator. It could be the same in yours; after all there's no functional difference between an alternator that can't charge the battery because of corrosion and one that can't charge it because of an intermittent fault (which is what happened to me). So the battery ends up dead and the garage fix that, but your next battery may end up dead, too.

The only thing you can do is ask a garage to check the alternator for you and let them know what's happened. Of course, if it's an intermittent fault they may not find anything.

Sorry to be the voice of doom :(

On the up-side, a car of that age probably will still be controllable (steering, brakes, etc.) even at motorway speeds, so if the worst does happen you should at least be able to get onto the hard shoulder safely.
posted by gmb at 11:28 AM on November 12, 2012

mosk is right: if "everything [goes] off," that sounds like a fuse, or equivalently, a break in one of the battery cables. The only thing is, many engines will keep running even if you disconnect the battery. So I'm wondering, even if one of the cables broke, what caused the engine to stop? (Obviously, if you'd turned the engine off, you wouldn't be able to restart it, but it stopped while you were driving, right?)

Alternator problems often go together with battery problems, and in some situations, just fixing half the problem will cause the other half to damage the half you thought you'd fixed. So I think you might be well served to have someone check your alternator, too. Perhaps the garage that helped you out also did that. I can't imagine they'd be offended if you asked whether you need to check or worry about the alternator, after the battery repair.
posted by spacewrench at 11:35 AM on November 12, 2012

This problem definitely could have been caused by corrosion in the battery cable - typically the negative battery cable.

Seconding this. No earth connection means no power, even if the alternator is working fine. Don't worry, I think it is fixed.
posted by Brockles at 11:50 AM on November 12, 2012

I had that problem myself a few weeks ago, and it was corroded battery cable.
posted by St. Alia of the Bunnies at 12:08 PM on November 12, 2012

If it's the battery, I suggest in the future you utilize a battery terminal protection spray. This will help keep the corrosion down. If you do find future corrosion, you can purchase battery terminal cleaner and clear away the corrosion.

All the the above is simple, cheap and can be performed in your garage with no need for a specialist or a mechanic.
posted by lstanley at 12:40 PM on November 12, 2012

I had a problem like this as well - it was a bad connection between the battery cable and the battery, and the car would just completely turn off with no warning.
posted by needlegrrl at 1:17 PM on November 12, 2012

This has happened to my older cars many times. The cheap fix is to mix water and baking soda, unhook the battery cables and use a toothbrush and your mixture to clean them prior to reattaching.
posted by M.C. Lo-Carb! at 1:34 PM on November 12, 2012

Corroded Battery Cable, perhaps dead battery.

This happened to me, and dead, dead, dead. Had the car towed to the dealer. They replaced the cable (the battery was fine) and everything worked like a champ.

If the battery doesn't connect to the rest of the car, you can forget getting it going.
posted by Ruthless Bunny at 1:37 PM on November 12, 2012

The froth on the battery cleaned-with-baking-soda thing happened frequently enough on a new Ford that we quit buying Fords. It is advisable to keep track of where the resulting mixture goes. It will mark your garage floor.

Incredibly enough, a garage reversed the cables on the battery of another car. They denied it, but the automatic speed control never worked again. So we take our non-Fords to a different garage.
posted by Cranberry at 1:52 PM on November 12, 2012

What it sounds like (to me) is that the alternator could slowly be dying- a sign of which is the corrosion & death of a battery sans any leakage/other explanation for corrosion. Replacing the battery is a good start, but knowing for sure whether or not an alternator is also in need of replacement will prevent future recurrences of the corrosion and wearing down of a battery.

Are you mechanically inclined enough to run a simple test on the alternator? While the vehicle is running, simply pop off the red connection (+) from the battery; if the vehicle continues to run fine, then it was indeed the battery, however if the vehicle dies/turns off quickly (or even gradually) then you know it's the alternator, too. Or, if you are not so inclined, many auto parts stores offer free testing of alternators. If they are busy it may take time for a tech to free up and drag the machine out to the parking lot, but even then it's still a free test; this will clear up your question(s) as well as not involve the original mechanic!

Good Luck : )
posted by MansRiot at 4:12 PM on November 12, 2012

Response by poster: Thank you very much everyone for your answers - you have both put my mind to rest but also given me the prod I needed to get the alternator looked at.
Thank you!
posted by schmoo at 10:35 PM on November 12, 2012

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