Well sure I'm old school, but one of the products of combustion is carbon and today's engines are built with lots tighter tolerances than they were in years past and carbon is an abrasive. Low twenty something dollars for five quarts of good petroleum oil and a good filter from Walmart is cheap presence of mind to get rid of the dirt. I'm sure that the fuel injected engines today have way less fuel dilution than we had up here in the frozen north with the chokes on the carburetors. I had this conversation with our east coast sales guy who subsequently called me from the repair shop to eat crow when he thought that he could run his oil 25,000 miles because the advertising said that he could.
