If your car battery was stolen twice in just a few days, you've likely been scammed by thieves who take your old battery knowing you'll drop in a new one—that they then come back and steal. Clever, right?

But you can outwit the bastards, says NYC auto-repair-shop owner and Don't Get Wrenched blogger Elayne Kling, by taking the following measures. 

  1. Rig the hood closed with a cable and a lock. "We did this in the '80s, when crackheads were stealing spark plugs," Kling says. 
  2. Buy a system—a cross bar/lock or a lockbox—to lock the battery in. If you can't find one for your car, ask a mechanic if he can weld one. 
  3. Temporarily pop in an old battery from your mechanic. (Be sure it isn't leaking acid and won't hurt your car.) Even if the thief takes it—though he probably won't bother, since it won't be worth selling—you'll be out only a few bucks. Once he's moved on to other suckers, put in a new one again.