340,000 miles, Change oil to 5W-30?

[HawkX66]

5 = the oils flow rate.
20 or 30 = the oils protection rating.
It will always flow at 5w.
Also any 5w is semi synthetic blend even if it says conventional, that’s how they get it to 5w weight.

and my thoughts and experience are yours to consider, I can’t speak for anything else.
JS from PA

Just so it's clear what someone else started to point out, NOBODY should be listening to this guy. He has no idea what he's talking about. My consideration of his experience is that he's worked at a quickie lube stripping oil drain bolts for too long. The only thing worse than not giving advice is giving bad advice.
Going to 5w-30 isn't a bad idea. Oil treatments are.