By The Book Comic

High viscosity oils such as 10w30 are thicker, which creates more resistance to engine parts and reduces engine performance. This additional drag caused by oil can increase fuel consumption and reduce fuel economy. 5w30 is a great all seasonal oil for use at low starting temperatures as well as high summer temperatures. It is also more economical as it creates less resistance to bearings and movement of engine parts. But you need to understand that Motor oil 10w30 is thicker and can provide better tightness for older engines. As engines get older, their clearances widen and require thicker oil for better protection.