Which statement best describes the purpose and method of inspecting piston ring seals?

• A. Check piston crown temperature with an infrared camera and adjust ring gaps accordingly.
• B. Visually inspect ring lands and perform a dye penetrant test before reinstalling.
• C. Measure crankshaft end float to determine ring clearance.
• D. Assess wear and gap using feeler gauges and bore measurements, replacing rings if gaps exceed specification to restore compression.

Answer: (D)

The key idea is evaluating piston ring seals by checking wear and the actual ring gaps with precise tools, then restoring compression by replacing rings if the gaps are out of spec. Piston rings seal the combustion chamber and control oil, so their effectiveness depends on correct end gaps and proper bore wear. Using feeler gauges to measure the ring end gaps and taking bore measurements to assess wear directly tells you whether the rings will seal properly. If the gaps are larger than specifications, compression leaks past the rings, so replacing the rings helps restore compression and seal.

Infrared temperature checks and adjusting gaps by heat imaging aren’t how ring seals are validated; heat readings don’t indicate correct mechanical clearance for sealing. Dye penetrant inspection can reveal cracks but isn’t the standard method for determining whether ring gaps will seal, and it doesn’t address whether the ring gaps meet specification. Measuring crankshaft end float isn’t about ring clearance at all; it checks shaft axial movement, not how the rings seal against the bore.