Originally Posted By: jtaylor
i am dissatisfied with mobil 1 because the last time I ran it, it came out really dirty and cruddy after just 5k, i can't stand Royal Purple because it caused my engine to feel like it was running a 0w oil in it after about 1500mi, just not enough oil film at all, and the pennzoil ultra is acceptable, like I said, but it's not amazing, i'm not floored by how smoothly the revs feel. I mean, Ill take the ultra over the other's, but i'm looking for something exceptional.
Those crazy Japanese cars! ;-) My Audi's recommendations go all the way from 20w-50 if I so desire in the summer to a 5w30 or lighter in the winter. So, I tend to run Mobil 1 Delvac 5w-40 all year.
As others have pointed out, it would be nice if manufacturers continued showing different recommendations for different ambient temperatures. Considering where you're located, I don't think you're going to have a lot of problems going to a heavier oil. As long as it meets the specifications, there shouldn't be a problem, and warranty shouldn't be a problem, either.
If you're worried about "dirty and cruddy" oil, you should be able to find an HDEO that meets the viscosity and specs you require and prefer, and it'll be a lot more shear resistant.