Q: I took my 3-year-old Subaru Forester to the dealer for routine service. When I returned at the designated time, I was informed they had to replace the battery because it was dead. There were no prior warnings or indications of a battery problem. Is it normal for a battery to suddenly die like this?
-William
A: This is unusual!
Failing batteries typically provide warning signs such as slow cranking, dimming or brightening headlights, or the need for an occasional jump start.
Since you didn't ask for one or more of these symptoms to be investigated, nor authorize replacement prior to it being done, my assumption would be the dealer replaced the battery under Subaru's 3-year, 36,000-mile warranty, possibly because of leakage or excessive terminal
corrosion.
Or maybe the battery, checked with a conductance tester, tested marginally, and they had no qualms giving you the 5 o'clock
surprise!
Perhaps this is a good time to mention some battery care best practices:
Secure battery mounting, to prevent vibration damage, keeping terminals clean, and avoiding repetitive or deep discharging can help extend battery life. Heat is also destructive but isn't something one has much control
over.
Vehicles that are parked for long periods can benefit from a solar charger (a Battery Tender 021-1163 is one option) or a plug-in float charger (Battery Tender 021-0123). I listed these because both contain circuitry to prevent battery-damaging overcharging from occurring, even if left in use for long periods
of time.
Modern solar chargers, even the cheap ones, are now powerful enough that they should be paired with a charge controller. Exceeding 100 milliamps charge on a long-term basis is potentially
destructive.
Many vehicles don't power the lighter socket when the key is off, so a dash-top solar charger may need to be connected directly to the battery or another hot-at-all-times connection. It would be nice if solar panel manufacturers would provide a connector to plug the charger into the vehicle's data link connector under the instrument panel instead of the lighter
socket.
Q: My 2011 GMC Sierra 2500 4x4 has begun to follow grooves and ruts in the road, especially when I'm coming to a stop. I checked the tires, and they are full and not unusually
worn.
This morning, the anti-lock braking system light came on. Any idea what's causing these
problems?
-Jacob R.
A: Yikes! I'm highly concerned you may have a faulty wheel bearing that's allowing enough wobble in the bearing-hub connection that the wheel speed sensor has been scraped to the point of
failure.
You can check my theory by safely jacking each front wheel off the ground an inch or so and checking for movement or looseness when grabbing the tire at two opposite spots and tugging
on it.
There should be practically zero movement. I should add that if movement is noted with hands at 9 and 3 o'clock, but none at 12 and 6, this indicates steering system looseness rather than a wheel bearing issue. GM wheel bearings are incorporated within a rather pricey bolt-on hub assembly and are known to give trouble. Don't delay getting this checked out!
ABOUT THE WRITER
Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at [email protected]; he cannot make personal replies.