Dear Tom and Ray:
My 88-year-old mother has a 2005 Buick LaCrosse with 15,000 miles on it. It only gets driven to the grocery store, hair salon and church. But that has been the case for all six years she's owned it. Now, in the past three months, three new batteries have gone stone-cold dead after four to six weeks! The Buick service department says the problem is "She doesn't drive it enough!" Heck! For nearly six years, she "didn't drive it enough," and it used the same battery! I can't get them to tell me why it apparently is sucking the life out of the batteries now. Any ideas? — Gary
Ray: Well, I agree with you, Gary. If the problem were that she didn't drive it enough, why did she have no problem with the battery for the first six years?
Tom: There are two possibilities. One is that something inside the car is draining the batteries. It could be a faulty alarm system, dome light or some other electric accessory.
Ray: The dealer should be able to figure that out by putting an ammeter on the car when it's shut off and seeing if there's a current drain.
Tom: But I think the more likely problem is that her charging system isn't working.
Ray: Here's the scenario: She drives the car a few times a week. Normally, that's enough to recharge the battery. But at some point, the alternator starts to underperform.
Tom: Without the battery recharging properly, in the course of a few weeks or a month, the battery runs down and dies. So she takes it in. They don't test the system rigorously enough, and just sell her a new battery.
Ray: At first, everything seems fine, but the new battery isn't being sufficiently recharged either. So it lasts for a month or so, and then it dies. This process is repeated three times, until you realize that the guys at this particular service department are complete knuckle-scrapers and you go somewhere else.
Tom: Where, hopefully, they do a thorough test of the charging system, figure out what's wrong with it and replace the alternator or whatever else needs to be replaced.
Ray: And if you end up needing another new battery, it's perfectly reasonable for you to go back to the original dealership, explain to them that they missed the problem with the charging system and ask them to reimburse you for the battery or three they sold you. Good luck, Gary.
(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk website.)