Which of the following are signs of overheating in a reciprocating engine?

High cylinder head temperature and illuminated warning lights are indeed signs of overheating in a reciprocating engine. The cylinder head temperature is a critical parameter in monitoring engine health; excessively high temperatures can lead to engine damage or failure. When the cylinder head temperature rises above safe operating limits, it indicates that the engine is running hotter than intended, which can be due to insufficient cooling, air-fuel mixture issues, or other mechanical problems.

Illuminated warning lights serve as a crucial alert system for pilots and maintenance personnel. When these lights activate, they typically indicate a potential failure or hazardous condition, such as overheating. The combination of elevated cylinder head temperature and warning lights serves as a strong indicator that the engine needs immediate attention to prevent severe damage. This understanding of engine temperatures and warning indicators is vital for safe operation and maintenance practices.