Being here in the Pacific NW, I run a winter front when tems drop down to 55 and lower. I made my own from a BBQ grill cover from Wal-Mart ($15). Its 15 miles to work and she warms up quite a bit quicker.
Two weeks ago I went on an hunting trip over Tonasket WA, 600 miles round trip. Ran the grill cover the entire time, no trailer, 65 mph average speed on I90. Coolant temps 185-220. IAT 100-140, 130-140 going over Tiger, Snoqualmie, and Blewett passes. Fan kicked on a few times for a mile or so. Coming back half way up Snoqualmie it kicked on for a few miles...pulled over and opened up the transcooler holes and it never came on againg. 21 mpg average on winter blend diesel.
2005 LLY, LBZ mouthpiece, PVC reroute "Homemade Kit",EDGE CTS, EGR Blocker Plate, 4 inch Silverline exhaust, Xfer case pump rub kit, 285/75/16
Southern by the grace of God, Pacific NW by the order of Uncle Sam
Machinist, F-15 and C-17 engine mechanic