What are the symptoms of a damaged cylinder?

[DeIsabela]

When an engine cylinder is damaged, the following symptoms may occur: Gas leakage between adjacent cylinders: Without opening the decompression, when turning the crankshaft, it feels like both cylinders lack sufficient pressure. Black smoke appears when starting the engine, the engine speed drops significantly, and there is an obvious lack of power. Cylinder head leakage: The compressed high-pressure gas enters the cylinder head bolt holes or leaks from the joint surface between the cylinder head and the engine block. Light yellow foam can be seen at the leakage point, and in severe cases, a "hissing" sound may be heard, sometimes accompanied by water or oil leakage. Gas and oil mixing into the oil passage: High-pressure gas enters the lubrication oil passage connecting the engine block and the cylinder head. The oil temperature in the oil pan remains high during engine operation, the oil viscosity becomes thin, the pressure decreases, and the oil deteriorates quickly. The oil sent to the upper part of the cylinder head to lubricate the valve train clearly contains bubbles.