New part failure!

Just because a part is brand new in a sealed bag does not necessarily mean that it is perfect.
In my thread, what's inside https://permies.com/t/372741#3771965
I document the assembling of a 2003 Subaru 2.5 engine.
Along with the new short block, I purchased a new factory oil pump and a new in-the-bag factory crankshaft seal.
As I documented, the build and install went well.
The motor started and ran perfectly, with no leaks.
We made a trip to town for its test run, and after returning home, the engine now had 140 miles on it.
Ran great, no issues, big smiles...
Until the next day, when I casually went to check the oil, and OMG, it's down 1/2 quart!
Looking underneath, there were no puddles, but there were drips on the timing cover and oil filter, as well as parts of the exhaust system!

To access the oil pump, I had to remove the alternator, timing cover, timing belt, and tensioner.
The oil pump has no gasket, but uses a "form a gasket" instead.
It has one internal high-pressure O-ring and a traditional "lip" seal on the crankshaft, pretty straightforward.
My guess was that I had missed one tiny spot with the gasket maker.
Upon removing the oil pump, it appeared the gasket was fine, but upon closer inspection from the rear, I could see the back of the crankshaft lip seal.
A portion of the rubber was missing!
I had installed this seal while the pump was on the bench, could not have been easier.
But apparently, a brand-new seal from Subaru was old enough that the rubber had deteriorated; running the motor and getting it up to operating temperature was just too much for an aging seal to handle.
Luckily, I had two more brand-new seals on the shelf.
I will be watching the oil level closely for the next few trips to confirm that the second seal is doing its job.
,

We made a 200-mile round trip yesterday, and the oil level did not change; problem solved!
A ten-dollar seal that could have taken out my $1300 short block!

Have you checked the oil in your vehicle lately? How many miles since you had it changed? What about the air filter? Changed that lately?

When I was young, a brand-new VW cost $1,995, and a brand-new high-performance Corvette cost less than $5000. (A huge amount in 1971)
If you wanted them to last, you had your oil changed and your air filter checked regularly.
Now, a cheap vehicle is $25,000, and expensive ones are closing on $100,000
Even at $10 a quart and $25 for an air filter, maintenance is Cheap! compared to replacement.

As a side note, not all oil change places are honest or knowledgeable about the different needs of modern cars.
They hire young, ambitious employees. still wet behind the ears, they pay them minimum wage. They mean well, but... as the saying goes, "dumb as a box of rocks!"
Take your car to a reputable mechanic, the same mechanic you use on every rig you own.
Your vehicle will get the proper maintenance it requires, and your investment will last much longer.

Envious of the kind of mechanical prowess you have, Thomas.......  My dad had that from his farm days, but he did not pass that down once he moved to the city and had his family.  Still, his interests in DIY were infectious and my tinkering today comes from that. My wife's first car was a brand new '68 VW bug, bought to go to college--as you noted, around $2000 at the time.  In the mid-80s, my first car was a 1970 Squareback, purchased in Salt Lake City and sold in Corvallis, Oregon.  Keep it oiled, drive fast enough to bring fresh air into the vehicle, and make sure you have the spare tire filled with air so that it can power the windshield washer fluid!  And if starting is a problem, try crawling underneath and knock on the solenoid with a wrench, ..... or a rock,...whatever works.  :-)  What a car!....the pancake, flat-head rear engine was such an icon.