Thanks for the replys guys.
I checked the price of Mobil 1 yesterday.
It is R300 south african rand for 4 litres.
That is expensive here.
That is why I want to go back to mineral oil.
I can get a damn good mineral oil (which I plan to use) for about R100 south african rand. Because I do lots of town driving I would then change it every 8000km to keep it nice and clean.
But Mobil 1 I would only use on a turbo and a race car.
This thing is to buy groceries and huddle along where the family needs to go.