My local Honda dealer, where I get my oil changed, switched from Castrol to
Mobil oil. Also, the paperwork and windshield sticker no longer indicate
the grade or weight (should be API service SJ "energy conserving" oil, SAE
5-30 viscosity, for my particular year and model).

I had an impression from years ago that Castrol was considered a superior
brand. Is that still true, and if so, why?

The service manager at Mel Rapton Honda in Sacramento, CA, says one reason
he switched is price. Mobil is cheaper. And he assures me it meets all the
factory specs, although I can't verify that because I can't see the label
for what they put in my car.

He also says that all Hondas come with Mobil oil in the crankcase from the
factory, whether in the US or Japan. Is that true?

OK, so Mobil is cheaper. Assuming the product is marked as meeting the
factory specs for my car, is it good enough?

I am not asking here about synthetic oil; please limit responses to
conventional oil products only.

And please, I hope to hear informed and expert knowledge here, not
speculation and guesses. Thank you.

- Don