5-Quart Castrol GTX Magnatec 5W-30 Full Synthetic Motor Oil $14.57 w/ S&S + Free Shipping ~ Amazon By admin | July 17, 2018 2:59 pm EST 0 Comment Checkout via Subscribe & Save. 5-Quart Castrol GTX Magnatec 5W-30 Full Synthetic Motor Oil $14.57