Best GMC Synthetic Oil for Cold-Weather Starts
Hearing that gut-wrenching metallic clatter during a -20°F cold start in your GMC Sierra is enough to make any truck owner cringe. When the mercury drops, standard oils thicken into a molasses-like sludge, leaving your valvetrain bone-dry for those critical first seconds of combustion. I spent three weeks testing twelve different dexos-approved synthetics, documenting flow…