We had some cold weather in washington last month, down in the 0 to negative ranges. I run 10-30 castrol 75000+ oil in the old girl and she started up just fine for those days. Yes the starter was slow but that comes from the cold, plus my passanger side door didn't want to shut one day I really had to slam it to get it to shut. Now it opens and shuts just fine because it has warmed up. Bitter cold does really stupid things to cars, they do things that they wont normally do when its that cold. Just pray for warm weather and hope that your starter hangs in there untill it warms up, I have had to change starters in 15 below weather and there were points when my hand would freeze to the starter. Not fun and I don't wish it on you.