“I’ve been told that the “High Mileage” oils are better oils for any engine due to their anti-wear additives that aren’t present in regular oils. Is this true?”
You need the oil called for by the manufacturer. New additives are made for newer engines and are compatible with anti-wear coatings you find on certain cars. I believe the additive you want is called ZDP. (Zinc Di-Phosphate, as I recall.) You may not be able to get the exact oil called out by the manufacturer. If not, call the company and ask them what substitutes for that oil today. Alternatively, join a car club. Bring a chair and pot to p*ss in ‘cause they’ll chew your ear off.
Sorry General. Just realized I was pinged to an old thread.