Originally Posted by danez_yoda
If they are old enough to allow conventional oil in the manual, this will be like sleeping in silk sheets.
Correct
Unless those old GMs are GDI/TGDI, one or two OCIs of Kirkland will be a breeze.
When one particularly notices the benefits of a good name brand oil in GDIs, is when it's used for a lifetime of the vehicle. Always read labels and product websites also. Then compare. Sometimes the differences listed are obvious and plain-as-day.... provided one can read, retain and comprehend.
The old GMs noted above should breeze right thru the limited use of Kirkland / Warren synthetic. Nothing wrong with saving money, where the shoe fits.