If you own a car with high mileage, it has long been recommended that owners use high mileage motor oil in their engine. This is specifically designed to protect engines which have some age behind them. The older a car gets, the more important the oil that you use in it becomes.
Compared against regular motor oil, high mileage motor oil displays superior protection. It also contains far more additives which cling to the metal inside your engine and coat it consistently for the benefits. As it is thicker, it will also help to seal leaks and seepage.
Both oils have positive and negative properties that can assist your engine. Castrol GTX is one of the better known performance oils which are recommended for higher mileage vehicles. There is no particular best high mileage motor oil, but there are many that will benefit your car more than others. Sometimes it is a case of trying out a few and seeing which one has the best properties for your vehicle. Valvoline Maxlife synthetic oil is also recommended by many mechanics for older cars.
High mileage motor oil is considerably more costly than regular oil, but the benefits to your engine can be worth it. It is always a matter of personal choice as to whether you decide to continue using high mileage oil. If you can judge the performance of your vehicle for any significant changes for the positive by using high mileage motor oil, then you will know the benefits. If you experience no particular changes, then switch back.