On Sun, 28 Aug 2011 22:47:51 -0400, "Ed Pawlowski"
wrote:


"Steve Barker" wrote

the manuals already say 3,000 mi under sever service. 95% of people fit
this category.


Doubt it. Just thinking about my neighbors, of nine cars I know of. three
fit into the severe category. Of ten cars at work, two definitely do, two
are questionable. While my informal survey is not scientific, it is a far
cry from the 95% figure you use.

Fact is, no one can give an absolute number of miles for large groups of
people. The best way, of course, would be oil testing. Some cars to have
some soft of algorithm that does give you a time to change based on driving
habits, miles, etc. If the people that are covering the warranty give
higher miles, I'd say they are rather sure of the numbers.


I was a dealer service manager for 10 years. At that time.
aproxemately 10% of my 600+ regular customers' driving patterns fit
the "normal" schedule, while about 70% were definitely "severe" and
the other roughly 20% were borderline - or they met several of the
requirements for "severe" at least part of the year. There is not
just the two extremes - so some customers stretched the change
interval part way - changing at 4000 miles (6000km) etc.