What action should you take when collecting an oil sample using the drain?

When collecting an oil sample using the drain, it is important to ensure that the sample represents the condition of the oil within the sump, rather than a potentially contaminated or stagnant portion. Draining enough oil to remove any stagnated oil ensures that the sample reflects the current state of the lubricant, including any wear particles, contaminants, and additives that may have settled or separated.

This process helps avoid the collection of oil that may not accurately indicate the overall health of the system, which can lead to misinterpretations in maintenance decisions or equipment assessments. By allowing for the removal of the stagnant layer, the technician can obtain a more representative and accurate sample that will be more useful for analysis and subsequent actions based on the oil's condition.

The other options either fail to ensure the integrity of the sample or suggest practices that do not align with standard oil sampling procedures, potentially leading to inaccurate assessments.