I have to replace my block heater on my LLY and figured I might as well replace the coolant as well. I have never changed the coolant in a duramax. How much do these trucks hold? Just want to know what size drain pan and how much coolant to add afterwards. I live in Michigan and plan on using the premixed 50/50 dexcool. Any special procedures for achieving the correct level when refilling? I’m aware of where the bleeder bolt is. Any info is appreciated!