Dear Tom and Ray:

OK, guys, I went to buy a 1997 Honda Accord for my mom. But those dealers always have something new up their sleeves. This time it was "Cathodic Protection" (aka Auto Saver System). It's a little gizmo connected to your car's battery that sends a pulse to your car's body that changes the polarity so that rust doesn't form, even if the paint gets scratched. According to both a Ph.D. in mechanical engineering and a chemical engineer/metallurgist I know, this process is legit, and has been used for years to protect underground pipes in oil wells and nuclear power plants. The problem is, neither of my sources has ever heard of this technology being used in a car. It sounded like too much of a good thing for the bargain-basement price of $319 (half off retail, just for me!), so I passed it up. But I must admit, my curiosity was piqued. Does this thing work? -- Kris

TOM: Yes, it does, Kris. And it's been shown to make a big difference if you happen to be one of the following: an underground pipe, a fuel storage tank, an off shore oil rig, or a car salesman with a $319 boat payment due.

RAY: Unfortunately, we've never seen any evidence that it does a lick of good on cars. Why? We don't know. It may have to do with the fact that cars are not all one piece, or that those other items are constantly submerged. And cars, unless you spent last winter in Seattle, generally are not.

TOM: So until we see some independent research that demonstrates that cathodic protection helps prevent rust on cars, our position is that you did Mom a big favor by passing on the "Auto Saver System." I'm sure she's much happier that you spent that $319 on a 10-CD changer for her ... so she can listen to her Grateful Dead albums on her way to and from bingo games.