10-ton - I can't comment on the Cat, but I ran my Racor 660R on the frame rail all last winter (without the heater hooked up), and it was fine. At one point, the truck sat in 0 degree weather for 3 days straight, and started right up on the third day, early in the morning. I do run an additive at all times (FPPF).
I'm thinking if you're getting a winter blend already, then an additive, it has to be pretty darn cold to cause problems. Hope this helps.
Josh