How many current members successfully run their engines a grade or two below what is "recommended" in the owners manual with good/bad results? For example running 0w20 in an engine calling for 5w30, etc. Kind of similar to how this guy used Neo 0W5 in 1.9TDi for 25k miles, an engine that usually calls for 5w40 oils.
Uh, from a 5w-40 to a 0w-5 is "a grade or two"...?
Well, IMHO 5w-30 would be one that might work...? Or a 0w-40 might even be an upgrade. Or the 0w-30's are usually pretty good oils, highly rated..?
But what about a 5w-20...? What's that HEAVY 40 WEIGHT spec in there for, anyway?
Maybe a 10w-40 would be OK in Phoenix when ambient temps are 100° at night... Or that 0w-5 in Nome, but for winter driving only?
I'm so confused! Why?