A SAE 20W-50 motor oil is typically used in older vehicles or in particularly warm climates. Castrol GTX 20W-50 has been specially formulated to help extend the life of your engine by keeping it free from sludge, even when operating in extremely high temperatures.
Whether you choose high mileage 20W-50 or conventional 20W-50 motor oil, they will both flow like a 20 Weight oil in cold weather, then with the viscosity of a 50 Weight oil once the engine is up to full temperature. Choose Castrol® GTX® 20W-50 to protect against sludge and Castrol® GTX® High Mileage for older vehicles with over 75,000 miles on the odometer.