A 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.
Castrol® GTX® High Mileage 20W-50 is specially formulated for vehicles with over 75,000 miles. It contains Phosphorus Replacement Technology, which reduces the level of phosphorus and replaces it with a proprietary additive that preserves your emission system while maintaining robust wear protection. Castrol® GTX® 20W-50 is formulated to clean away existing sludge while preventing new sludge formation to help extend engine life. It is also liquid engineered to resist viscosity and thermal breakdown.