Supertech vs. Syntec (O'Reilly)

In all of my old GM vehicles i get a noisy- piston slap- startup with a 5w30 that is not there with a 10w30. I run a 10w in them year round in PA w no issues, synthetic or blend or dino never mattered
 
I wonder how O'Reilly is able to use the Syntec name without getting sued by BP? I'm guessing the trademark expired since Castrol no longer has that name on their labels.
 
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