Help me understand my car problem?
January 5, 2019 7:12 PM   Subscribe

You are not my mechanic. But maybe you are *A* mechanic? My car’s starter crapped out on New Year’s Eve. I got it to a mechanic who replaced it, it began starting like a dream, hooray. Now today the battery inexplicably died. What’s up?

My car (2007 Civic, 106,000 miles, in very good shape and maintained well) died on Monday. AAA came and checked the battery and to my surprise, it wasn’t the problem, it was the starter. I had the starter replaced and all was well.

I made two trips in my car today, and everything was fine. Got home, parked for an hour, and then it wouldn’t start, in a clearly actually dead-battery way (confirmed with the mechanic and a faraway relative who knows things about cars). Checked that the battery was actually connected. Wiggled the cables and said some bad words, which (unsurprisingly) did not help.

I haven’t tried jumping it yet but am going to later tonight. But I’m concerned about what’s going on here and how apocalyptic it is. Is this the end of my car or might there be an explanation that isn’t terrifying? I don’t have huge knowledge about engines, so any ideas may help. Thank you!
posted by centrifugal to Technology (14 answers total) 2 users marked this as a favorite
How old is the battery? A car battery has a finite lifespan; if it's been a few years, it could just be that it needed changing. It drives me nuts when multiple things go wrong on my car in a row (shouldn't you have seen that when I brought it in before, mechanic?) but it could just be a coincidence, or your battery coming to the end of its life and hastened on by the starter.

Last time my battery died, it was in the parking lot at my son's school--it was fine getting there to drop him off and just wouldn't start up again.
posted by gideonfrog at 7:36 PM on January 5 [3 favorites]


posted by sanka at 7:36 PM on January 5 [1 favorite]

Not to threadsit but the battery is dated 2014. Could this actually be a horrible coincidence?
posted by centrifugal at 7:38 PM on January 5

Very unlikely to be anything apocalyptic. If the battery is dead, it's because a.) the battery itself has had an internal failure b.) the alternator is failing to recharge the battery as the car is driven (bad alternator, or, less likely, bad wiring or a bad electrical load detector- not present on all Hondas) c.) there is a some sort of current draw which is draining the battery while the car is off.

It's possible but unlikely that the battery terminals or a ground strap were not properly resecured after the repair and aren't making good contact. Even if they seem tight, the only way you really know is to use a voltmeter and check for voltage drops.
Chances are it's just the battery.
posted by Larry David Syndrome at 7:38 PM on January 5 [2 favorites]

Interestingly, I did actually have a very similar issue where the starter of my car was replaced, the car started for a while, and then failed with dead battery symptoms. It was due to the battery contacts being corroded at some point, causing inconsistent contact with the battery terminals. A volt meter showed this trivially.

I agree that this is unlikely to be apocalytic and that it likely you merely have a dead battery (five years is a long time for a battery!) or a connection issue.
posted by saeculorum at 7:45 PM on January 5

the battery is dated 2014.

...and here we are in 2019. Batteries last about five years -- even less these days, I hear.
posted by Rash at 7:51 PM on January 5 [13 favorites]

I had the battery/starter stop working within the same week combo happen on my last car, and once I replaced them both the car ran without problems for at least 5 more years.
posted by lepus at 7:58 PM on January 5

The mechanic’s test that showed the battery problem would be the same test done to show most other electrical problems. So, it was your battery just taking a dump. It happens.

This is presuming you didn’t, like, leave a dome light running and didn’t notice it.
posted by Cool Papa Bell at 8:45 PM on January 5

It's probably not apocalyptic! I am not a mechanic, but I've done more than my fair share of amateur mechanic work.

You already replaced the starter. I'd suspect the next two things to check would be your battery (can it hold a charge?) and your alternator (can it charge your battery?).

This should be relatively straightforward for a mechanic. And, if you're comfortable checking some stuff out yourself, you might be able to determine the problem (and maybe even fix it – replacing your own battery is totally doable, and many folks are comfortable replacing their own alternator – check YouTube).

To check the battery, you'll need a multimeter. This multimeter is currently only $11.

Here's a guide for How to Check a Car Battery with a multimeter. And here's a guide for How to Test an Alternator.

If you need to replace the battery, you should absolutely consider doing it yourself. There are great instructions available, and you can probably find a video walkthrough for your exact vehicle on YouTube.

You may even be able to replace the alternator yourself, depending on your comfort level with mechanical instructions and tools. The most important part is the diagnosis. If you're not sure what the problem is, it's probably not a great idea to go replacing things. But if you get confident that you need a new battery, that's a pretty great problem to have (among all the problems that result in "car won't start").
posted by reeddavid at 11:32 PM on January 5 [3 favorites]

I would bet battery over alternator. I've had both go in the past. The alternator happens while driving (that's when it's doing its work) and it's a slow process - stereo turning off, lights dimming, dash meters conking out one by one. The battery is sudden and tends to happen between starts, or rather flashes out when trying to start up.

Batteries tend to get about a 3-5 year life span these days, unless maybe if you live somewhere with a perfectly neutral climate. Change it yourself, no point paying someone an extra 50 - 100$ unless it's hard to access and requires removing other engine components. DIsconnect the negative before the positive, unscrew the casing holding it in place, drop in the new one, reverse the order of previous instructions. I do it every 3 years now regardless of how things are working - my local auto parts store sells them with an automatic 3 year warranty, not a coincidence I imagine.
posted by mannequito at 11:46 PM on January 5 [1 favorite]

Not a mechanic, but I've seen something like this pretty recently...

Sounds to me like the guy who replaced the starter messed up a contact to the alternator, or maybe forgot to hook it up... when that happens, your car will start and run fine for a while on just the battery, but then stop (or not start) once it's drained.

A bad alternator or battery could produce the same symptoms, but I'd say the timing suggests a bad contact. And with an older car, getting those contacts right can be tricky.

To find out, after you jump-start your car, measure the voltage at the alternator (should be about 14V if it's good), and then also measure the voltage across the battery terminals (should be the same if connections are good).

- If the alternator voltage is <13.8V, that would suggest a bad alternator
- If it's good but the battery voltage (when the engine is running) is different from that, it's probably a bad connection
- If the battery voltage (when the engine is running) is >13.8V, the engine keeps running, but then later won't start, that would suggest a bad battery

Oh also, if it's just a bad contact, unnecessarily replacing a perfectly good alternator or battery would also likely fix this... if you let your mechanic do the diagnostics, I hope you trust them...
posted by kleinsteradikaleminderheit at 2:37 AM on January 6 [3 favorites]

If it's clicking when you turn the key, it could be the solenoid on the starter or it could be low battery voltage. Friend of mine once had a '98 Accord that would intermittently fail to start. A nice Optima Yellow Top covered up the issue for several months thanks to being able to supply more current, but it eventually started going "click" again. I was still convinced it was a bad connection (his battery cables were getting a bit wonky from age, so wiggled more than I care to see), but it was indeed the solenoid failing to actuate properly in the end.

After fixing that he was good for a couple more years until that case ended up partly wrapped around a tree on his way home from work one night...
posted by wierdo at 3:44 AM on January 6

If you have an AutoZone or Napa auto parts near you, they'll typically test the existing battery, and if you do need to buy a new one, replace it for you at no extra cost. I've changed my own batteries before, and it's typically really easy. That said, I drive a Subaru now, and the battery I just had replaced last Friday took the AutoZone guy a solid 10 minutes to replace...apparently Subaru does an insane job of fastening the battery down. I was glad I wasn't doing it myself this time (as it was also below freezing out at the time). Good luck!
posted by csox at 4:43 PM on January 6

I’m concerned about what’s going on here and how apocalyptic it is. Is this the end of my car or might there be an explanation that isn’t terrifying?

Nothing at all apocalyptic. Nothing to worry about. There is every chance that trying to turn a failing starter for a few months put the battery near the end of its rope and it just .... farted a gentle sigh of defeat and gave up. Especially likely in cold weather.

My bet is - change the battery, because it is due anyway. I always put the largest one that will physically fit in the hole personally, even if it is $10-20 more just because manufacturers tend to 'optimise' (ie scrimp) on battery physical capacity. When you replace the battery, wire brush and clean up all the connections and do the same with the earth lead where it connects to the chassis or engine. Good, tight and clean connections are key, here.

Double checks in case the starter fix screwed something (less likely, to me) - Clean and refit both battery connections. Follow wire from battery negative to the engine block or chassis and undo it, clean it and put it back. There is no earth connection on the starter as such (it earths through the housing) so it is likely the only battery wire that was disconnected during the starter change was the one at the batter itself and the starter itself. So if those are tight and clean, then that is not the issue. If the starter main wire is tight then you should be good to go.

The battery is pretty much lifed out - such that I'd just replace it as a matter of course, and then I'd keep an eye on it. A slow charging battery (through faulty alternator) would have had trouble starting the hour before it finally died, so that makes it much more likely to be the battery to me.
posted by Brockles at 9:38 AM on January 7 [1 favorite]

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