At what temperature would the 0w have better flow vs the 5w, I am a Mobil oil guy and I loved the 0w 40 FS in my vortec series gm motors. but it's a little thicker than I'd like for my new 6.2 silverado possibly, and it's had a very high count of additives which may not be good for a DI and low speed pre ingtion. I've been monitoring the water temp and oil temp and gm is running these motors hotter than id perfer, water temps of 215 normal driving and 230 at times of hard acceleration. Pulling a trailer id imagine is even higher. That puts oil temps in the 230s. Factory fill is 0w 20. I feel that's pretty thin for these engine opperating conditions. I've been looking at Mobil 1 5w 30 and the 0w 30 afe . I haven't decided yet on which one of the two or possibly a different Mobil oil selection. Winter temps typically don't go below 0 degrees Fahrenheit.