Only six brands are on the list of GM4718M approved motor oils. Any idea why so few? Is it too tough of a standard for brands such as Amsoil,Royal Purple, Valvoline, etc., to meet? Or, do these c ...
I'am Sorry ! I am not a GM employee, I guess GM4718 is not mandatory standards. So, the certification only a few products. Full entry criteria may GM6094.Maybe not !