Yep colder weather I'd run 5/40w Rotella and in TX I run 15/40w. Works well, I've had 15/40w in my LR in colder weather and it didn't tick/knock at startup, but if I lived up north where there is actually 4 seasons I'd certainly change my oil weight per the conditions.

 

Just to update the thread, I had no problems at all running 15w40! Not even weird noises from the engine. The rover was a beast in the snow this trip.

Thanks everyone!