Castrol GTX 5W-30 Synthetic Blend Motor Oil, 5 Quarts

Customers find this motor oil performs well in various vehicles, including 07 Cobalt 2.2, and appreciate its excellent price and convenience, with one noting the 5-quart container makes oil changes easier. The oil keeps engines running smoothly and stays clean inside, with one customer reporting it runs great for over 10 years. Customers disagree on whether it's fully synthetic.