>>28469807The difference between a 25 year-old nip car and a sub-10 is that one if them will have "adding 1 liter of oil per 3000 miles is normal and not eligible for an engine warranty claim", or a similar statement. Burning oil from day 1 is partially caused by low-friction piston rings
>everyone does it>not just nips>but also bioshas consequences, and the long-life oils with 18 to 20 thousand-mile service intervals compound this even more. In truly catastrophic cases, the cylinder bores wear out so much they become oval instead of circular and then you can't do anything about it, since engines have cylinder coatings instead of liners these days and that is not compatible with reboring in a workshop (so you gotta buy a new block, and at that point, why not a new engine or a new car). Catastrophic failures aside, the coated bores are weak and wear out under such conditions (if a bit more evenly), the dirty oil that is circulating in the engine for an eternity helps destroy valve stem seals (which again are underbuilt these days) and sludgy oil eventually kills the hydraulic variable valve timing actuators.
The bottom line or all of these failures is that a modern end-of-life engine, even (especially?) if it's nip, will burn more than 1 liter of oil every 1000 miles AND get noticeably worse gas mileage than it did new, and at that point, you can't pass emissions. I've seen that "fixed" by shady mechanics installing a temporary exhaust system that diverts part of the exhaust into a concealed exhaust – an emissions tester that plays along and doesn't look too hard will see normal readings on the main exhaust. That much oil and unburnt fuel also kills cat converters, which throws up a check engine light and automatically fails you when doing Smog.
This engine wear is deliberate, engines are designed for a trouble-free 120k miles. With this target lifespan, they usually become unfeasible to keep fixing at 200-250k.
>>28469882And here they are