Can Fully Synthetic Engine Oil Still Be Used After One Year of Opening?

[Bridget]

Fully synthetic engine oil is not recommended for use after being opened for one year. Here are specific methods for selecting engine oil for cars: 1. Performance selection: If you prioritize the long-term effectiveness of the oil, you can choose Mobil oil; if you focus on the oil's cleaning effect on the engine, you can use Shell lubricants; if you need lubricants with strong oil film toughness, it is recommended to use Castrol. 2. Driving conditions: For frequent driving in congested areas, older vehicles, or long-distance heavy-load transportation, the viscosity of the lubricant can be appropriately increased. 3. Engine type: For naturally aspirated engines, mineral oil or semi-synthetic oil can be used. Compared to naturally aspirated engines, turbocharged engines have a more compact structure and operate under harsher conditions, requiring higher-quality lubricants with better fluidity, preferably fully synthetic oil.