Red Seal Automotive Service Technician Practice Exam

What is the correct order of operations when changing engine oil and the oil filter?

1. Drain old oil, refill with new oil, replace the oil filter

2. Replace the oil filter, drain old oil, refill with new oil

3. Drain old oil, replace the oil filter, refill with new oil

4. Refill with new oil, replace the oil filter, drain old oil

The correct answer is: Drain old oil, replace the oil filter, refill with new oil

The correct sequence when changing engine oil and the oil filter involves first draining the old oil. This step is crucial because it ensures that the old oil is completely removed from the engine, allowing for a thorough replacement with fresh oil. After draining, the next step is to replace the oil filter. Changing the filter ensures that any contaminants that have been trapped in the old filter do not circulate back into the engine with the new oil. Finally, refilling with new oil is the last step. This order not only prevents contamination but also guarantees that the new oil is clean and effective from the moment it enters the system, ensuring optimal engine performance and longevity. The other choices disrupt this necessary sequence. For example, refilling oil before draining or changing the filter could lead to confusion about the oil level, poor filtration, and potential contamination of the new oil.