What are instant failure reasons for an older (not old-timer) automobile?

Question

I usually drive my commuting cars until they are quite old - at the time when repairs start to crop up, the amount and frequency of repair bills dictating when I get a new(ish) one.

So far, I never had a problem where the car failed instantly during a drive and I had to get towed off.

Do you know hard numbers/statistics of how much more likely it is for older cars to catastrophically and unexpectedly fail on the road, compared to new/middle age cars? The only frequent reason I know of is if the timing belt snaps => game over. Are there other things that happen reasonably frequently?

Some context:

• Car is regularly checked as per manfucaturer's specification and state regulations (Germany / TÜV). It's not a lump of rust. In addition, it gets a quick eye-over by my favourite mechanic every time he changes summer/winter tire.
• All of the usual wear&tear is replaced promptly, oil changed, brakes/tires changed etc.
• Normal or defensive driving, no racing. I am the only driver, so I know nobody did much wrong with it.

The question is meant to be rather general, not targetted at a specific car or make. In my case, that would be a petrol engine (not diesel), medium sized, 10 years, 220 Mm. I'm not even sure if that is considered "old" these days, or at which age cars normally start to fail because of age.

Answer 1

Well, there's a few things:

• alternator dies: you will be running on battery only until that drains (usually 20 minutes), and then game over (I had this happen)
• distributor rotor snaps: another instant game over (I had this happen)
• tie-rod end snaps: while this won't MAKE the car stop, you'll hear a heck of a racket and vibration the next time to turn a corner and you'll stop all by yourself to go take a look (I had this happen)
• fuel pump dies: instant game over, and I hope you didn't get a full tank of gas recently
• a coolant hose snaps: you will leak coolant until the engine overheats and either autoshuts off or seizes
• a transmission hose snaps: you will leak transmission fluid until the transmission overheats and seizes or simply loses hydraulic contact with the flywheel (for an automatic)
• throttle cable snaps: this won't stop the car, but it will slow you down to idle speed. You can definitely limp home, but it will take a long time, and you won't be able to go up any hills

As you can see, I've had the first 3 happen. That being said, it is a myth that older cars break down more often than newer cars. Generally speaking, people severely neglect their maintenance and therefore, the older a car gets, the more likely it is that something will go. People who truly do all their maintenance and look at something as soon as the first trouble signs appear can have their car live a good long time.

Also, new cars are susceptible to defective parts. Even though they are brand new, sometimes they have defective parts that will fail very quickly. That's why new cars have a warranty. Warranty isn't a magic word that means it won't break, it just means you may not pay for the entire repair if it breaks.

Think of it this way: a new car has never been started in -20 weather, never hit a big bump, never bumped the curb, never had 500 kg of people and stuff added to it, never drove through the rain, never did an emergency stop. The first time a new car does any of these things is a stress, whereas older cars have parts that have gone through life.

Also, how "old" a vehicle are you talking? Some people think 6 years old is ancient, some people think old is 10 or 20 or 30 years old. 3 of my 4 cars are over 20 years old.