Donald Snook wrote:
So, is the point of going 15-20,000 miles just so you can say you did
that? No matter anyone’s thoughts about the price of Mobil 1, I think
we can all agree that it is cheaper than an engine. This thread has
demonstrated that people have an almost religious belief about the oils
they use in there cars. I suppose I am no different in that all I could
think was “Oh God! Why would someone go 20K on the same oil.”
If the oil becomes dirty and requires changing at 1,000 miles, there is
NO argument that it shouldn't be changed. If it doesn't require changing
for 20kmi there is absolutely NO reason to change it sooner. It's all a
matter of how dirty it gets. Different driving styles with different
engines and different conditions will dictate the change interval. There
is NO single interval or even pair of intervals that is best! All the
manufacturer can do is provide a VERY conservative estimate that will
assure safety under arguably worse case conditions. That usually results
in 75-80% of the oil being discarded before it's life is even half
exhausted. A little measurement and some common sense can allow the SAFE
extension of oil change intervals by 100-200 or even 400% even using a
conservative criteria (2% soot for example).
It makes no more economic sense to discard oil with half or more of it's
life left, than to discard half the fuel you buy rather than burning it
all or discarding half the food you buy without eating it!
Marshall
--
Marshall Booth (who doesn't respond to unsigned questions)
"der Dieseling Doktor" [EMAIL PROTECTED]
'87 300TD 181Kmi,'87 190D 2.5 199Kmi, '84 190D 2.2 227Kmi, '85 190D 2.0
159Kmi, '87 190D 2.5 turbo 234kmi
Diesel Technical Advisor MBCA, member GWSection
http://www.dhc.net/~pmhack/mercedes/mbooth1.htm
