> Because they are made out of treated paper and they start to
> disintegrate before they are replaced. BMW has acknowledged that is a
> problem.
>
> The long term oil change intervals are based on limiting the number of
> trips to the dealer for the first owner, and the expense to the
> manufacturer on cars that include maintenance, ie BMW. If it lasts till
> the warranty is up they don't worry about it.
Another thing to consider is that some cars hold a lot more oil than
others.
Our Bimmer V8s hold 8qt of oil and the filter element is (guess) 1.5x
the size of a traditional FL1A-or-similar quart-size spin-on filter.
Yes, there's no question that the service intervals are fudged a little
to ensure that the big maintenance items don't occur until outside the
free/prepaid-service window. The 40K-mile BMW brake rotors come to mind...
John.
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