It has been VERY cold where I live over the past couple of weeks, as low as -30c (-22f). In my frozen stupor, I was wondering if a synthetic say, 10W30 would pump and flow way better than a conventional 10w30, or be very close. I realize that both oils must pass standardized tests to obtain the 10W designation, but does a synthetic "easily" pass vs a dino oil "barely" passing. And...is a synthetic 10W30 very close to a 5W30 dino with regards to flow and pumpability? How about after say, 3000 miles? How about a 15W synthetic like M1 vs a 5W dino like Pennzoil? Once I warm up I'll be OK...really! PS - I have M1 0w40 in one car and GC 0W30 in the other car, both work well in these temps. I have 5W30 in my truck; it isn't quite as good, as is probably to be expected.