Maximum protection against both viscosity and thermal breakdown. Unique Anti-Sludge formula. Castrol GTX's unique anti-sludge formula helps protect your vehicle from harmful sludge build-up. It's more than just oil. It's liquid engineering. Stop-and-go traffic. Harsh weather conditions. Extending your drain. These severe driving conditions can all cause sludge to build up in your engine, leading to reduced gas mileage, decreased performance, and in some cases, engine seizure. Protect your car from harmful sludge formation with Castrol GTX. Its unique anti-sludge formula provides excellent protection against harmful sludge build-up to help withstand the most damaging driving conditions. Castrol GTX SAE 10W-40 delivers: The highest North American standard of protection against viscosity breakdown. Excellent protection against thermal breakdown. Advanced anti-wear additives to help extend engine life. Superior detergency action to help prevent deposits. Exceeds: API Service SM/SL/SJ/SH. Exceeds the engine protection requirements of ILSAC GF-4, GF-3 and GF-2 for API Certified Gasoline Engine Oils. Also exceeds all passenger car and light truck manufacturers' warranty requirements for the protection of gasoline and turbo charged engines where API SM, SL, SJ or SH is recommended. A premium multi-grade oil, providing all-season protection. Made in the USA from domestic and imported components.