Castrol® GTX® High Mileage 10W-30 is the #1 consumer high-mileage brand of motor oil.  It's a synthetic blend engine oil that helps extend the life of engines by protecting against sludge, wear and burn-off.  Engineered with Phosphorous Replacement Technology, it also protects emission systems by replacing some of the phosphorous that can damage catalytic converters.  Meets or exceeds the following specifications: API SP/SN PLUS/SN/SM, ILSAC GF-6
- Phosphorus Replacement Technology helps extend emission system life 
- Superior dispersancy that fights sludge build up 
- Exceptional oil burn-off protection exceeding industry standards* 
- Seal conditioners to help reduce leaks 
- Advanced additives that minimize engine wear 
- Improved fuel economy** 
- * Based on API and ACEA volatility specifications 
- ** In 5W-20, 5W-30 and 10W-30 grades versus industry specifications