So it doesn't really get cold enough in Texas to warrant worrying about a grille blanket. However, the past few weeks of driving in Texas have been pretty cold. For some of my driving my LLY won't heat up all the way to just below 210. When that t-stat does finally open, it cools it back down. I'm worried about this hurting my mileage, but would a grille blanket block too much? Options?