Yesterday while I was on the way to the coffee shop the TPMS light came on in the Smart. Tires weren't flat so I figured I'd sort it out when I got home.

But that's not where the saga starts. The saga starts 8 or 9 months ago when some schmuck stole my valve stem caps. Nothing special, just generic gray-to-match-the-rims Smart factory stock caps. So I went to NAPA to get replacement caps. Saw nice shiny metal caps. Price was right. I bought them.

That turned out to be a mistake. The valve stems on the Smart are aluminum. As I was to learn months later, if you have aluminum valve stems, the best course of action is to use non-metallic valve stem caps. You'd think as the son of a corrosion engineer I would have seen this one coming and gotten plastic caps...

Fast forward to yesterday. I got home, but couldn't get the valve stem caps off. Figured they were probably just gunked on so I took a wrench to one.

The cap came right off... along with the top part of the valve stem - which had turned to a fine white powder. Of course I immediately knew what had happened.

We managed to get the car in to the shop this morning for new valve stems. Dodged a bullet by not having to get it towed there.