The difference between 5W30 and 5W motor oil The main difference between 5W30 and 5W motor oil is that the latter is less viscous (or thick) When used in a vehicle's engine, 5W oil creates less friction due to its thinner viscosity, meaning it causes less drag across engine parts like the crankshaft, valvetrain, and pistonsThe 5w30 and 10w30 motor oils differ by their viscosity The former is less viscous than the latter 5w30 is thinner than 10w30 at low temperatures Thus, 5w30 is better suited for colder regions where the temperatures dip to – 30°C But this multigrade oil will work well even at 35°CAlways check your owner's manual for the manufacturer's recommended oil viscosity grade, API service classification and any builder approval 5W 5W30* 10W30* 10W40 W50 Grade SAE 5W SAE 5W30 SAE 10W30 SAE 10W40 SAE W50 Density @ 15 C, g/ml, ASTM D4052 0874 Density @ 156 C, g/ml, ASTM D4052 0859 0859 0858 5w30 Vs 10w30 Engine Oil Viscosity Which Is Better Carcaretotal Difference be...