Help me not get swindled by car mechanics
March 1, 2014 11:45 AM   Subscribe

New (6 month old) car battery has died twice in the past month. From the pattern it's been showing, can you help me figure out what the issue might be, and help me avoid getting swindled in my attempt to get it fixed?

2 years ago I inherited my dad's 2002 Lexus RX300. When I went through the records, he seemed to be so-so about maintenance. Up until 6 months ago, it was running on its original battery, which I replaced 6 months ago during some major 90k maintenance. I drive it pretty infrequently, and only put about 1k on it since. I often go days without driving it.

It was running great up until a little over a month ago, when we experienced "polar vortex" on the East Coast, and had some extremely cold days. It was a little bit sluggish to start on those cold days, but only slightly so. Then I went 5 full days without starting/driving it - on the 6th day, it was fairly warm (45-50 degrees) and I attempted to start it. Some lights on the dash went on, but there was just a "rrrrrrrr" sound upon starting. Got a jump, and it started fine. From then on, things were ok - slightly sluggish to start on the really cold days, but fairly without issue (not sluggish when driven on subsequent days, slightly sluggish when skipping a day or two). That was exactly a month ago.

I was out of town this past week, and so my car sat for a full week without being driven, again in fairly cold temps. When I started it this morning, the dash lights again came on - radio even came on. But just a "rrrrrrrr" sound when attempting to start. No juice. Got a jump, and again it immediately started. I drove it to the dealer who changed my battery, and left the vehicle there for them to inspect.

Could the new battery be a lemon? Could it be the alternator? I had a full diagnostics done during the 90k, and am afraid of being swindled into a long list of more repairs than necessary. I'm told "the alternator could go at any time" and would not have come up during the diagnostics. Nothing was left on during either time the battery died.

From this pattern, what might you suspect is the problem?
posted by raztaj to Grab Bag (20 answers total) 1 user marked this as a favorite
Alternator. And if it is going, it should be diagnosable now.
posted by Kriesa at 11:47 AM on March 1, 2014

Sounds like an alternator problem to me, too.
posted by tealcake at 11:55 AM on March 1, 2014

Bad alternator. And take it somewhere else.
posted by cnc at 12:01 PM on March 1, 2014

The new battery might still be under warrantee; something very similar happened to us and we got ours replaced for free.
posted by wyzewoman at 12:02 PM on March 1, 2014

I had a problem like this - battery seemed to drain quickly only if I didn't drive the car. Turned out to be a short in the circuit breaker panel (not a breaker that needed replacing, an actual short)!

Alternator is the obvious first answer, and it's worth checking, but the key here is that the battery drains when you _don't drive_, even if the lights and everything are definitely turned off (if the problem is the alternator, then driving the car won't charge the battery). That means that _something_ is draining the battery. A short could explain it.

Checking the battery itself makes sense; my own battery was replaced twice on the way to figuring out this problem, but the battery had a warranty so it didn't cost me anything (so, get a battery with a warranty and work with guys who stand behind their work).
posted by amtho at 12:19 PM on March 1, 2014 [4 favorites]

It could be the alternator, but going by the symptoms you've described, there are other possibilities.

Both times you had problems were after the car sat for an extended period of time. When I had this problem, it was due to a slow battery drain occurring. In my case, it was a failed switch for the vanity mirror light in one of the sun visors. The light was always on, and it could drain the battery down enough for it not to start after about 3 days. You could have a small draw occurring in any number of places in the complex electrical system of a 12 year old Lexus. A good shop should be able to track down the source of the drawdown or should be able to recommend an auto electrical specialty shop.

When I've had a bad alternator, the car wouldn't be able to start itself again the next time after receiving a jump and running for a while, and would even stall after a significant amount of run time because the spark plugs were running off the battery and would eventually drain it to the point that they wouldn't fire.

Bottom line, the shop you've taken it to should be able to tell whether the alternator is the culprit with a simple test. If you don't trust them, or want a second opinion, most of the major chain auto parts stores will do free alternator testing.
posted by gimli at 12:23 PM on March 1, 2014 [4 favorites]

Yeah, I came in here to say what gimli said. Sounds like a parasitic drain. If it were the alternator, the battery which needed a jump to start the car would not have had enough to start the car later the same day.
posted by notsnot at 12:45 PM on March 1, 2014 [1 favorite]

Simple test you can do before you go to the garage: next time you are going to leave it out for a week without driving, disconnect the negative battery terminal. Should only take a minute, a small wrench, and probably you can do it without even getting your hands dirty. Reconnect the terminal when you return and see if it starts right up.

Also, you're at 100K miles on a 12-year-old car with basically no maintenance (aside from the routine maintenance you performed when you got it). Cars are expensive and that's a good run. Don't think the mechanic is ripping you off unless you have good reason to suspect it.

They may or may not be a good place, but you want to build a relationship with a mechanic you trust instead of hopping around to different locations for every problem.
posted by jsturgill at 1:24 PM on March 1, 2014 [1 favorite]

It's possibly a parasitic drain. However, take the car to your nearby O'Reilly/Auto Zone/ whatever the big auto parts chain store (not Pep Boys or anyone else who actually has a repair shop!) is near you, tell them what's going on and ask if they can test your car. Most of them can bring a cart out that will test the battery, alternator and starter, and it's a free service. If everything checks out, then you've got a drain somewhere. Maybe it's a trunk light that's not turning off when the trunk is closed or something odd like that. I am driving a car that has something draining it if it's parked a few days; it's the definition of a beater car and I'm not intending to keep it long enough to make fixing it worth it. I have a solar trickle charger that plugs into the lighter and that's more than enough to combat slow drains. I got it for $22 at the parts store.
posted by azpenguin at 1:29 PM on March 1, 2014

If you have a multimeter, you can check the system out yourself for a power drain. Multimeters are cheaper than a half-hour of labor at most mechanics.

azpenguin's advice is good as well. If you care to do so, you should be able to go into the mechanic with a lot of good information that didn't cost you anything/much to obtain.
posted by jsturgill at 1:31 PM on March 1, 2014 [2 favorites]

How cold is cold? We left our car outside for a week in the winter (in Fairbanks in December, so it was probably between -20 and -40 F) and it didn't start after that. And I think that's pretty typical around here.
posted by leahwrenn at 2:33 PM on March 1, 2014

As others have said, it sounds very much like a slow drain on the battery. I had this happen a few years ago. The trunk was fully latched, but the light inside the trunk stayed on. This was verified by putting a small daughter in the trunk and closing it (briefly). A hidden switch turns the trunk light on when the trunk opens, and off when it's closed. The switch had failed, and the light was continually on. It was a very inexpensive part to replace.
posted by Snerd at 2:54 PM on March 1, 2014

Another here vote for a slow drain --- yeah, I had one too, and when you added in that $&@! Polar Vortex, I ended up getting jump started twice in three days.... fun times.
posted by easily confused at 4:04 PM on March 1, 2014

I had an after-market alarm system of some kind in my car that I didn't even know about. It was slowly draining my battery when I wasn't driving it for days or weeks at a time. Heaps of mechanics looked at it and could only suggest a new battery. I went through about 6. Eventually I took it to an actual auto-electrician, and he identified the stupid alarm thing almost immediately, ripped it out, and charged me $40 for his time. That was about over 4 years ago and I haven't had to buy a new battery since.

tl;dr - take it to an actual auto electrician.
posted by Diag at 6:26 PM on March 1, 2014

If you don't drive it far when you do drive, it may just not be charging enough on those days to keep it full during longer stretches of really cold weather. This used to happen to me a lot, and my (very good) mechanic told me that I should just go out every few days and turn on my car and let it run for a few minutes to charge the battery.

Then Metafilter taught me about trickle chargers!
posted by dizziest at 8:12 AM on March 2, 2014 [1 favorite]

My husband has an auto repair shop.

He says you have something that is slowly draining your battery power when you car is off. When you don't drive it every day, whatever it is has the opportunity to drain your battery down. If it's not something obvious (like you're leaving your cell phone charger plugged in all the time) then you have to find the bad ground in your car's electrical system and fix it -- it could be anywhere. He says this will trash your battery over time so you may need a new battery now even if there wasn't anything wrong with the battery when you got it.

He says it's NOT your alternator because if it was, it wouldn't be fine after you get a jump.

He says your options are:
A) drive the car every day
B) pay someone whatever they charge per hour to take however many hours it takes to find the bad ground ($50-$100+/hour for an indefinite number of hours)
C) get a new car

He's pretty strongly in favor of option C as this is potentially a nightmare to find and fix unless you get lucky and they find it really quickly. He says you're pretty much at the mercy of the technician with this kind of problem.

If you do want to get it fixed without spending a ton of money, he says DO NOT go back to the Lexus dealership but instead find a A6 ASE certified technician (automobile electrical systems) to either do it on the side or an independent auto repair shop that employs such a technician.
posted by Jacqueline at 12:50 PM on March 2, 2014

Note: my husband says this is the sort of problem where he'd personally prefer to tell a good customer to take it somewhere else to get fixed because he'd hate to be the bad guy charging them $2,000 to find it.
posted by Jacqueline at 12:54 PM on March 2, 2014

Per what Jacqueline said, does the car have any aftermarket accessories installed like a stereo, alarm system or GPS? If yes, you might consider going back to wherever they were installed and ask them to check to make sure they were done properly. If you don't know or aren't sure that's still something to tell the certified technician to help give them a starting point.
posted by tommasz at 3:29 PM on March 2, 2014

My boyfriend had his battery replaced in his old Honda a few months ago, then a few weeks ago, his car wouldn't reliably start but never died after it started running. It was able to be jumpstarted, but once you turned off the engine, it would die again. They finally pinpointed it to be his battery cable, and that fixed the problem.
posted by madonna of the unloved at 8:03 PM on March 2, 2014

Thank you all for the replies, and this has been good lesson on all things and possibilities battery related. Since I had the battery put in at the dealership, they replaced it for free - according to them it had a bad cell. Hopefully that was really the true culprit and the car won't continue to die on me -- in any case I feel a lot more informed/prepared with information!
posted by raztaj at 9:51 AM on March 5, 2014

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