Prime Guard Full Synthetic 10W-30 Motor Oil is a state of the art, advanced technology motor oil which provides a high level of engine protection, even under the most severe operating conditions. Prime Guard provides exceptional resistance to high temperature oxidation thickening. Sophisticated additives prevent sludge formation commonly caused by moisture and combustion by-products. An exceptionally high viscosity index minimizes cold weather oil thickening, preventing battery drain and engine wear, even at subzero startups