How long does a car last? Three people have asked me that in the past six months. What they really wanted to know was: "How much longer will my car last?" My response always begins with: "It depends." It comes down to the kind of car, and how and where you drive it. The Midwest isn't called the rust belt for nothing. If you live in the south or southwest and never drive in ice and snow, chances are your car's body will last longer. Except with double-sided, zinc-galvanized steel, electro-phosphoric primers and high-tech undercoating, almost any car less than 10 years old tends to look pretty good.
The marque used to make a huge difference. Mercedes-Benz and Volvo had reputations for extraordinarily high mileage. Keeping a car for a half a million miles is still a pretty big milestone. At one time, the only real chance of going that kind of distance meant driving a car from Europe.
What parts have to last for mega-distances? Obviously the engine has to be reliable. It needs to be simple to work on (less chance of an incompetent mechanic screwing it up) and relatively under-stressed. No engines from Mercedes-Benz, Volvo or even the venerable air-cooled Beetle were cutting-edge. Horsepower was never a major concern; rather simple, strong and reliable.
Regarding the rest of the driveline-the transmission and drive axle-keeping it simple isn't stupid. A live rear axle and a conventional four-speed manual transmission is a recipe for durability. In general, a modest engine and transmission will almost always be adequate for long life. A Beetle trans, for example, was fairly fragile. But given the anemic power from its flat-four engine, it was more than up to the job.
Perhaps the most annoying and disruptive aspect of a European car has been its electrics. Jokes about the Lucas stuff found on British cars notwithstanding, the venerable Bosch company has no reason to cheer when it comes to its own history.
Failures were rare with the major systems; the car would almost always start and run. It was little things like headlights and turn signals that could never quite be counted on. It wouldn't leave you stranded in a parking lot, but it sure was annoying to drive home in a rainstorm minus wipers, with one window down. There was a time in the mid-1970s through the mid-'80s, (and then, ironically, again in the mid-'90s) when owners of high-end European sedans were never really sure if everything was going to work when a switch was flipped.