I agree with all the above comments with just one caveat: Some engines are more sensitive than others at cold temperatures to oil viscosity. For instance, one of these is the ford 4.6 v8 overhead cam engine so if it gets down below 0F take that into consideration. RW
Their specs show its pumpability limit is down at -42*f. New M1 TriSyn 10W30 seems to flow quite well at minus 5*f, which was as low as my icebox could manage. I would have zero concerns in the teens.
Dr T's up in Toronto & I'm north of Denver, & we're both giving M1 15W-50 a try this winter. (Al, are you doing this too?) I've already had a few tests in the teens this fall & haven't had any problems. (My engine's a 2.0L I4; not sure about Dr T's).
If you're really worried about it, ZR2RANDO routinely mixes grades without any problem, so you might consider MolaKule's suggestion & top up with M1 0W-30 for the winter.
quote:Originally posted by jessealan:
What happens to mobil 1 supersyn 10w/30 when it gets below 19f. I have got 3000 miles on the oil and I do not want to change it yet. As the winter gets going it will regulary be in the low teens.
It thickens to about 900cSt at 19*F. That's about 90 times thicker than at operating temperatures. In contrast, M1 5w-30 thickens to about 700cSt at 19*F.