Back in high school chemistry, you may have heard the teacher refer to water as the universal solvent.
Exactly so. It dissolved a mile of rock at the Grand Canyon, for instance.
And it will eventually dissolve your car, too.
Your old car, especially.
This bears some defining, though.
A fifteen-year-old car is an old car – but it’s not an old car for purposes of this discussion. No car built during the past 30 years or so is really an old car, nor will ever be one. Not in the sense that matters.
Which is the build quality/body integrity and rust-protected sense.
Cars built since about 30 years ago – ’90s and up – are almost hermetically sealed against the intrusion of water into places where it will foment rust. Their panels usually fit tightly and precisely.
As a result, they rarely leak. And if they do, the metal is generally better able to withstand the Ancient Enemy . . . rust.
On the other hand, cars built prior to 30 years ago – anything made earlier than the ‘80s – are typically rust traps. They have gaskets that didn’t fit very well and so leaked when new, letting water rivulet into places like the inner rocker panels and trunk – where it does to your car exactly what the Colorado River did at the Grand Canyon.
They have trim that seemed designed to catch and retain moisture, the grossest offender being windshield molding. Their sheetmetal was poorly aligned, insouciantly rustproofed, shoddily painted and easily chipped – exposing the raw, unprotected metal.
Get them wet and they will rust.
And rust faster.
That’s probably the main reason why you don’t see them around much anymore. It’s the real planned obsolescence. Engines in those old cars can can be rebuilt fairly easily – and pretty cheaply. Rusted bodies and frames are the opposite. Welding in new metal is hard – and expensive. Body and paint work isn’t cheap.