Highway miles is the best case scenario and the darkness of the oil is from the DI and doesn’t reflect on the condition of the oil.
Long highway sessions help with fuel dilution and are mechanically easier than short trips stop and go driving
And yes I would go 5k oci with Mobil 1 esp 0w30
Long highway sessions help with fuel dilution and are mechanically easier than short trips stop and go driving
And yes I would go 5k oci with Mobil 1 esp 0w30