Despite much better characteristics of Group III oils (over conventional oils especially) they still are (natural) petroleum with all imperfections. Volatility, cold temperature, oxidation resistance, tendency to make a varnish & sludge, ..., longevity are their real "weak points". So, why bother (ourselves) with conventional oils at all? I've started with synthetics before twenty years and (really don't know why) switched to Castrol some time later (influence of advertising maybe). When discovered their game with customers (and rules) I switched to synthetics - forever. Honesty of Mobil could be disputable. Check this:"...The "small percentage" of petroleum oil
in bottle of synthetic (according to
Mobil) actually is 9.8% to 19.2%.
Many investors would be thrilled to get
such a "small percentage" return on
their money !!
Just for the record - the average
dividends for Mobil and Exxon over last
20 years have been in 2% to 4% range,
and they jointly term this as
"significant" return on Shareholders’
Equity in their Annual Reports...".
I am not telling that their oil is bad but what is point of "discovering" 15.000 mile drain interval while, for example, "Optima 2000" oil (from former Yugoslavia) before 20 years had drain recomendation of 20.000 kms?