They change things and don't tell us about it until it is too late.
The 737 MAX crashed not because of an engineering flaw, but an information flaw. They had "maxed" out the size of the plane (sorry, pun) and using its ancient architecture, wedged in the largest engines possible on its tiny landing gear. To avoid FOD (Foreign Object and Debris) ingestion, they moved the engines forward and up on the wing. The previous method of putting the characteristic "dent" in the inlet cowling was no longer sufficient.
Problem was, this created weird handing properties and the possibility of a pitch-up condition. So they added an automatic system to pitch the nose down if this condition was detected. Problem solved! But suppose the safety system went haywire and pitched the nose down unnecessarily? No problem, just turn the system off and land the plane.
And that would have worked if they told pilots about this design change and installed a warning system that would advise them of the problem. To save money, they told the FAA that there were no significant design changes requiring retraining for pilots. To save even more money, they offered the planes with the warning system as an option. So when untrained pilots in third-world countries (whose airlines opted not to buy the safety system) got into this situation, they had no idea what to do - and everyone died as a result.
Companies do this - they change technology and hide the fact they changed it. A few simple instructions and education would solve a lot of problems, but most companies have a paranoid fear of disclosing basic information about their products, either fearing "trade secrets" would be stolen, or that somehow the information would be used against them in a lawsuit or something. Being tight-lipped is the norm for most companies, as a result.
I wrote before how ordinary technology such as lightbulbs, decking screws, and decking have changed, and unless you are a contractor (and even then...) you can literally make fatal mistakes by applying "old school" methods to modern technology. Some new forms of pressure-treated lumber will literally eat right through galvanized fasteners - causing a deck to come apart.
It is like the switch to LED light bulbs - you had to re-educate yourself about something as simple as the old 100 Watt bulb. Now we had to worry about "lumens" and "Kelvin" and like any learning curve, it is steep. You come home with a 5000 Kelvin bulb and realize it makes your house look like the examining room at the veterinarian. So back to the store you go - yet again!
With cars, the chances for foul-ups are even more common and costly. No one told us they changed everything and if you apply "old school" repair techniques to new cars, you can literally seize the engine.
Take antifreeze, for example. Seems like a simple thing, unchanged for decades. But it changed. General Motors introduced "Dexcool" lifetime coolant. Shade-tree mechanics thought they were doing a good thing by flushing their coolant but all they were doing was flushing money down the drain. Worse yet, mixing good old Prestone with Dexcool could cause all sorts of weird problems. And if you let the coolant level go low (as happened on a number of Chevy Blazers back in the 1990s) the air in the system would cause the Dexcool to turn into sand. Betcha didn't see that coming!
As more and more cars went to aluminum engines - or worse yet, aluminum heads with cast-iron blocks (or vice versa) you had to worry about galvanic corrosion. Special antifreeze and distilled water were required, otherwise you might blow the motor up.
It gets weirder. Ford had an issue with 1990's "Powerstroke" diesels in their pickup trucks. Seems that due to the vagaries of engine design, the coolant would cavitate when the number 7 cylinder fired. Cavitation can eat right through metal, as any boater will tell you - it happens to boat propellers all the time. Anyway, it would eventually eat through the cylinder wall and cause the engine to fail - that is, unless you added water wetter to the coolant. It makes water wetter! No, really, it reduces surface tension of the coolant and prevents cavitation. It's spelled out in all capital letters in volume 4 of the F150 service manual (for 1995). I know because I read it. Most people didn't - or even order the manuals. So Dad flushes the radiator with Prestone and figures this is helping extend his engine life, when in fact, it is shortening it.
Today, most cars can go 100,000 miles on the original coolant, and quite frankly, I kind of gave up on frequent fluid changes as a result - you can cause more harm that good!
Even if you use the correct coolant (BMW Blue) with distilled water, you can still seize the engine. On many cars, the cylinder head is higher than the radiator - particularly on inline-6 BMWs. A small "bleed screw" is provided on the cylinder head, and after flushing the radiator, you have to open this up and let the air out of the coolant passages in the cylinder head. If you don't, the head overheats and warps and you blow up the motor. But a lot of people don't realize this (again, you have to read the manual, even for "simple" tasks) and sadness results.
Modern cars don't have "coolant overflow bottles" like we had in the 1970s, Prior to that, most cars just dumped coolant on the ground. Today, systems are sealed and an expansion tank handles the excess coolant when it expands. It is all a sealed system, so no air gets in and thus no oxidation or rust. Oddly enough, opening the cap to "check the level" isn't helping, it's hurting by letting more oxygen in. Best to leave well enough alone.
Oil is another issue that they changed and didn't tell us about. There are so many specialty oils and weights for engines, transmissions, and differentials - and the wrong oil can destroy an engine or transmission or make it hard to shift. Even back in the day this was an issue. I bought a used Fiat that would not stay in second gear. The owner had drained the transmission and filled it with good old American 90-weight gear oil - the kind of oil you would use in a Muncie 4-speed. It wadded up around the synchros and popped it right out of second. Turns out, you had to use MT-5 fluid in that transmission, something I realized only after replacing the tranny.
Back in the day, you had 10W-30 and that was it. Then 10W40, 5W-20, 5W-50 and so on and so forth. And now we have synthetic, part-synthetic, and so on. And since cars run cleaner, the idea of the 3,000-mile oil change itself is obsolete. Some cars are reported to go as much as 20,000 miles between oil changes - with no adverse effects, long-term (not that I recommend it!). Again, the wrong oil can destroy an engine, and I'm sure it has been done.
Even lowly grease can bring tears. I am repacking the wheel bearings on the camper - something that some (such as Dexter Axle) say should be done annually or every 12,000 miles. Well, the camper is four years old and had 30,000 miles and I repacked only one bearing last year. Trailer wheel bearings use a design that dates back decades. If you had a '66 Chevy, you would be familiar with the tapered-roller bearing design. Trailer manufacturers are starting to move to sealed hubs (much as many modern cars and trucks have). The bearing goes bad, you just replace the whole hub - it bolts on. The bearings are sealed for life (the life of the bearing, not you) and no more greasy sticky mess in repacking the bearings every year!
We ran into a Lesbian couple in New Hampshire with a huge 5th wheel trailer. It came with sealed bearings but the previous owner "didn't trust them" and removed them and replaced the hubs with old-fashioned tapered roller bearings. Apparently he didn't install them correctly - he over-tightened the castle nut which should be hand tight on smaller axles or even backed off a quarter turn or so on larger axles. The bearings failed and a wheel fell off and when I met these ladies, both axles had been removed and they were awaiting replacements. Ouch!
But even if you don't tamper with perfection, you can still screw the pooch. Turns out, there are multiple kinds of grease out there, the two primary kinds being Lithium-based and Molybdenum-based. If you mix the two, they attack and destroy one another and the grease turns to runny liquid and your bearings fail. Some fun! Again, it pays to read the manual which isn't all that hard (they also have a 99-page manual, but that is over-the-top).
Sealed bearings for life? I'm there! Greasing wheel bearings is so yesteryear. But that's what I have, so-be-it. Another "change" to trailering is the use of disc brakes, which are a marked improvement over dusty old drums. With boat trailers, though, you have to be aware that you can't back up unless the boat trailer is connected to the brake controller on the tow vehicle (with a reverse wire hot!) as the brakes will "lock".
Of course, for many folks all of this is a mystery and will remain so. I see people by the side of the road with a flat tire, waiting for AAA to come change it. They have "roadside assistance" so why get your hands dirty changing a tire? Just pay for the service! Besides, they have no idea how to change a tire anyway. Our vaunted rugged independence and self-reliance has gone by the wayside.
And perhaps this is because they keep changing the technology and not telling us about it!
