🔍 Key Concepts

• Function of oil control rings on a piston • Purpose of drain holes in the oil control ring grooves • What happens if oil cannot drain from the ring groove back to the crankcase

💭 Think About

• Think about where the oil is supposed to go after the oil control rings scrape it off the cylinder wall. • If the drain holes are blocked, what builds up in the ring groove, and how does that affect the oil film on the cylinder wall? • Which option describes a direct mechanical result of trapped oil around the oil control ring, rather than a secondary or more distant effect?

✅ Before You Answer

• Identify the primary job of the oil control ring (not compression, not sealing combustion gases). • Decide what happens to the amount of oil on the cylinder wall when it cannot drain properly through the groove holes. • Eliminate choices that describe results that are less direct or that would typically be caused by other problems (e.g., fuel issues, general lubrication loss).