If coolant comes into direct contact with the cylinder liner, then what type of liner is used?

When coolant comes into direct contact with the cylinder liner, a wet liner is used. This design allows the coolant to flow around the liner, providing effective cooling for the cylinders. The wet liner is typically inserted into the engine block and has coolant passages integrated into it. This physical connection between the liner and the coolant system helps in maintaining optimal operating temperatures within the engine, which is crucial for performance and longevity.

Wet liners are especially beneficial in situations where rapid heat dissipation is necessary, making them the preferred choice in many modern engine designs where temperature regulation is critical. The full contact with the coolant ensures that heat transfer is efficient, thereby preventing overheating and contributing to smoother engine operation.