Semi Synthetic 10w/40 is a fuel-efficient multigrade engine oil meeting current API classifications. Semi Synthetic 10w/40 is manufactured from a balanced blend of top quality mineral and synthetic base stocks, producing high quality engine oil with the properties of semi-synthetic technology. Its naturally higher lubricity offers lower internal friction for reduced engine wear. Its low viscosity offers improved flow rates and hydraulic tappet performance during cold start and engine idling, a problem with many higher viscosity oils.