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.
At 09:14 PM 9/13/2004, Trevor Boicey wrote:
>Bill Engle, Sr. wrote:
>>The oil will probably last 15,000 miles, but there is no way that the oil
>>filter will last that long. 7,500 should be the longest interval.
>>Bill
>
> ...and why not?
>
> In a modern clean-burning engine, that has always used modern oils,
> there just isn't a whole lot of "stuff" floating around to filter...
>
> The people who wrote the manual know the product inside out, have run
> thousands of models, simulations, tests, research, analysis, etc. etc.
>
> Especially in this case where they are stating a service interval that
> is actually _longer_ than conventional, why would you want to do anything
>else?
>
> 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. Maybe if they were saying 1,000 miles you could
> say they were being pessimistic and cheat a bit, but...
>
>--
>Trevor Boicey, P. Eng.
>Ottawa, Canada, tboicey@brit.ca
>ICQ #17432933 http://www.brit.ca/~tboicey/
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