> I guess it's a pet peeve of mine though... I often see people who
> just don't understand the depth of knowledge that people who design
> stuff for a living have about the products they create. I'm not sure
> whether they think "they know better", or probably more likely, assume
> "nobody really knows, better be safe".
>
> The truth is, people know, that's their job. If they are saying
> 15,000 miles, they have reasons.
That's all true enough, Trevor. However, as I'm sure you know, what the
engineers say is frequently not what winds up in the owner's manual.
Plus, engineers are always given design guidelines ... maximum life at any
cost is NOT usually one of those guidelines.
The "reason" for that 15,000 mile oil change interval may well be that they
wanted to limit dealer costs during whatever period oil changes are "free".
That would be balanced against some majority of the engines lasting until
outside the warranty period, which is rarely over 100,000 miles ... whether
an engine will last 200,000 or 300,000 miles is rarely a factor for a car
maker.
But the car owner generally has different priorities than the maker.
50 years ago, car makers were arguing that oil filters were not necessary at
all. Independent tests showed otherwise ...
Randall
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