Hi fellas, I have a 90' Dodge with a Cummins and I do not always have access to a source of power to plug my truck in when it gets cold out. I am concerned about the length of time it takes to build oil pressure when it's not pluged in which is sometimes up to 10-15 seconds. I am running 15w-40 Rotella right now and would like to know if I can stay at the same weight and go to synthetic or can I go to a thinner weight oil and not change to synthetic after all of these years. I personally like the man made stuff but I am concerned about developing oil leaks if I switched. Thanks for the advice. Kurt.