If you have cold winters you might want to use synthetic then for faster oil flow on cold starts.
He lives in Austin, TX. They don’t get too darned cold there, except by Florida standards.
I still believe these high-mileage oils are a gimmick. I’ve several vehicles last well over 300k miles and at worse they burned less then 1/2 pint every 5k miles.
Yes. Fear of mixing different major brands of oil which met the same specifications was/is pure marketing. When I worked at a Chevron station as a teenager our oil brand was Chevron. The Texaco station across the street’s oil brand was Havoline. We had a lady customer who insisted on Pennzoil 10/30 for her Cadillac. Of course we kept it in stock for her. Today my Kia dealership uses Chevron Havoline oil for my services. I also miss the old interesting brands.
When I joined in 1977 Army and Air Force jet turbines ran on JP-4 which was basically kerosene with up to 20% of AVGAS (high octane gasoline added). Most ground motor vehicle were diesel with a few exceptions which used MOGAS. I think it was a low octane (82?) gasoline. Jet turbines could run for a limited number of hours on alternate fuels. We joked that it could be Aqua Velva after shave. In the early 1990s NATO went to JP-8 as the standard fuel for aircraft, ground vehicles and generators. Of course similar to the US insistence of standardization of NATO small arms ammunition of the 7.62X51 cartridge Which was rather quickly changed to the current 5.56X25 The NATO fuel became “Do as we say, not as we do”. The US Navy stayed with their JP-5. The Air Force experienced carbon buildup on compressor blades and created JP-8+100 which added commercial 100 low lead AVGAS.
At the 1964 NY World’s Fair, Chrysler did a demo with their Turbine-powered car in which they (supposedly) ran it on Napoleon Brandy. Of course, nobody knows for sure exactly what was in that bottle.
Motor Trend said at one time that a turbine could run on “peanut oil”. Probably true but not for long.
During the first oil crisis in 1973/74, companies used all sort of stuff for fuel. Used motor oil was often just filtered and then heated and fed into the power plants. large diesels would easily burn such stuff.
When I retired, the major national carrier I worked for poured their used oil in the fuel tank of the tractor it came from. Don’t know if they still do. Made them smore and run bad , nut they didn’t care.