What is the viscosity of engine oil and why is it important?

The viscosity of an engine oil is its ability to resist the flow. The viscosity of the oil directly affects how effectively it will lubricate engine parts under various operating conditions, especially at extreme temperatures.

The correct viscosity ensures a thin but strong oil film between the moving parts of the engine (pistons, crankshaft, camshafts). This film prevents direct contact of metal surfaces, reducing friction, wear and overheating.

If the oil is too thin, the oil film may rupture without providing adequate protection. If the oil is too thick, it will be difficult to pump through the lubrication system, especially at low temperatures, which can lead to oil starvation when starting the engine and increase the load on the oil pump.