Can 0w and 5w engine oil of the same brand be mixed?

[AdrianFitz]

According to standards, engine oils of different brands and specifications should not be mixed. However, in emergency situations where only a small amount is needed, mixing oils of the same brand is generally not a big issue. Mixing engine oils of the same brand: When topping up engine oil, it is best to use oil of the same brand and specification. If oils are of the same brand but different specifications, they can be mixed, but long-term use is not recommended. Hazards of mixing engine oils of the same brand: Engine oil is primarily composed of base oils and additives, and oils of different specifications are certainly not identical. If two oils of different specifications are mixed, although the lubricating properties remain unchanged, the composition of the oil will inevitably alter. This change in oil composition may adversely affect the engine, hence long-term use of mixed oils of the same brand but different specifications is not advised.