Can anybody cite a real life case or experience where whatever oil was used properly for routine maintenance every year or every 150 hours, there was a problem?
I use Chevron Delo 400 15w 40
https://www.walmart.com/ip/Chevron-D...E&gclsrc=aw.ds; it has a answer for every thing the oil czars wishes to throw out as important. I use it in the F-53 and Onan 5500.
With that said, if I wanted to be technically prudent, I would change oil twice a year regardless of hours. October with the Chevron Delo 400 and 6 months later in March with my favorite 30w oil of the day (This assumes you live in the South where it gets really hot; otherwise stick with the 15w 40