To buy the right oil you need to know SAE Viscosity Grade and API Quality Index oil for diesel or gasoline engine. You can select any Brand from the listed.
Example: for gasoline engines Cadillac Ct6 (1st generation) 2016, suitable multigrade synthetics oil 10W-40 quality SN+, SN.
For bodies made in 2018, for the cold season, well suited synthetics 0W-40 \ SN+, SN.
If possible, check the selected oil for compliance with the manufacturers specifications and service intervals.
Checking the Engine Oil condition