It's kind of funny. My first oil change was with Esso XD3 0W40 full synthetic about 2007, it was only available in Canada, at Walmart amongst other places. Priced in line with dino oils. AFAIK they changed the name to Mobil Delvac for North American distribution, using that since.I work the heck out of my GC1720, maxed out snowblowing and heavy loader and digging work. I’ve been using Lubrication Engineers 10W30 Ultra oil. It runs about $25 per gallon which I consider reasonable. Sure Walmart oil may work just as good, who knows, but I’m happy with what I’m using.