A worn cylinder counterbore could cause which of the following issues?

• A. Upper sleeve flange separation
• B. Excessive sleeve protrusion
• C. Sleeve cavitation
• D. Piston damage during installation

Answer: (A)

The question tests how a worn seating surface for the cylinder liner affects liner stability. The counterbore in the block provides a precise shoulder that supports and aligns the top flange of the liner. When that counterbore wears, the liner’s top flange loses proper seating and can no longer stay firmly pressed against the block. Under assembly loads and engine pressures, the liner may shift or the flange may separate from its seating, compromising the seal and allowing misalignment or leakage.

The other issues aren’t direct results of a worn counterbore: excessive sleeve protrusion isn’t typically caused by wear of the seating shoulder, cavitation is a coolant-flow phenomenon around the sleeve rather than a seating issue, and piston damage during installation usually stems from misalignment or interference during assembly rather than from the seating surface wear at the liner’s top.