Why don't cars rust as badly as they used to? — Auto Expert by John Cadogan

Galvanised Steel

For the past 30 years or so, cars have been galvanised. Quick primer on galvanising >>

At least, the steel used to make the major panels has been. I’m talking about within the developed world. Even today, a lot of cars made for the domestic markets of China and India are without galvanisation and they continue to perform the same way as the cars around here did in the 1970’s, which is that they rust really easily. You get those bubbles of rust after only a few years.

Modern cars don’t seem to do that, and they haven’t done that for 30 years.

It’s really easy to understand why. It’s because the steel used to manufacture modern cars is hot-dip galvanised right at the end of the steel manufacturing process. Essentially galvanising is that whole "sacrificial anode" thing that Anthony is talking about.

However, they don’t use a big fat chunk of zinc bolted to the body like they might with a ship, an oil rig or a really long transcontinental pipeline for oil. They use a thin coating of zinc instead.