An SAE 20W-50 motor oil is typically used in older vehicles or in particularly warm climates.
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.