i have had my astra dti work van from 4 years old and it had done 40k miles when i got it, its now done 183000 miles and the engine and turbo is still untouched, it has been run on 20w40 mineral oil for all those miles at about 7000 miles service intervals.

it has been used all year round for 10 years in it, and all our machines run on it to all year round.
my 720 hp rb26 had been running 20w60 for at least 6 years and over 10k miles and still going strong.