If you change at 5k or less, there really isn’t a best. Syn blends can compete in this mileage range. When you start going into the 20k territory is when it’s only logical to try a top tier oil. I’ve seen Mobil 1 ep put up a good fight in 20k+ intervals here and elsewhere. I’d never touch...
If I could get it at a good price, I’d use Napa everything tbh. Love their oil and would love to try out their filters. But their prices aren’t the most competitive even when on sale.
Personally, I think Napa synthetic is solid oil and will serve both of these engines well. It’s currently on sale too. Check out the lake speed video where he compares it to amsoil and royal purple
Then I’m willing to bet your engine is quite clean, especially at those short intervals of Mobil 1 ep. Have you ever taken your valve cover off or put a scope down the full tube to see what the valve train looks like?
Imo if vrp didn’t help then hpl isn’t gonna do much either. There’s a guy with an oil burning Hyundai suv that went down this same path here and didn’t get anywhere. I think something mechanical needs to be addressed in your Volvos engine
no oil burning and valve train is pretty clean? Stock up on Kirkland or supertech and chug along. Any engine with 350k and no oil burning was taken care of by the prior owners