Hi,
from Jan 1997 I had these OCIs (over 8 oil changes) in three different engine families;
Average = 18kkms (11k miles)
High = 24kkms (14.9k miles)
Low = 9.3kkms (9.3k miles)
blsnelling - you said this;
"The oil you use has nothing to do with when the oil light will come on. Nothing in the oil is measured by the computer. This is calculated based on engine parameters measured by the many sensors on it. None of the sensors meausure oil viscosity or TBN."
This is only partly correct - the latest oil sensing devices used on some vehicles do in fact measure both viscosity and (effectively) TBN
and some are oil composition sensitive! The pages are still being writ..................
Regards
Doug