How Long is the Shelf Life of Engine Oil?

[Freddy]

Engine oil has a shelf life of five years after opening. Below is relevant knowledge about automotive engine oil: Methods for selecting automotive engine oil: For new cars, choose a lower viscosity 5W30; for older cars, opt for a higher viscosity 5W40. European and American cars should use fully synthetic oil with slightly higher viscosity, while Japanese and Korean cars are better suited for lower viscosity 5W30. If frequently stuck in traffic, choose lower viscosity oil; for frequent highway driving, select higher viscosity oil. Avoid using extremely high viscosity oil just because the oil pressure gauge reads low in summer. Functions of automotive engine oil: Lubrication and friction reduction: forms an oil film between two sliding components to prevent friction during operation, ensuring smooth movement. Cleaning and dispersion: high-quality engine oil can flush away dirt from component surfaces and absorb tiny metal fragments inside the engine, which are then scraped into the oil pan by the piston oil ring.