What does it indicate if oil flows 5% faster than the test sample in a dilution test?

When oil flows 5% faster than the test sample in a dilution test, it indicates that the oil has been diluted more than 5%. Dilution generally refers to the mixing of a less viscous or lower density substance with a more viscous oil, causing the overall flow characteristics to change. If the oil exhibits a faster flow rate in comparison to the test sample, this suggests that the presence of a diluent has altered its properties, leading to the conclusion that the oil is indeed more diluted.

In this context, faster flow indicates a change in viscosity and density that typically occurs with dilution, making it clear that the oil has been affected by another substance, rather than just having contaminants or experiencing overheating. Such factors would not inherently lead to an increase in flow rate during the test; instead, they could cause changes in viscosity, but with different implications on the flow characteristics. Therefore, the correct conclusion is that the oil has been diluted more than 5%.