When coolant contacts the cylinder liner directly, what type of liner is used?

When coolant contacts the cylinder liner directly, what type of liner is used?

• A. Dry liner
• B. Wet liner
• C. Plastic liner
• D. Metal liner

Answer: (B)

When coolant contacts the cylinder bore directly, the liner is a wet liner. Wet liners are part of the cooling system and sit in the water jacket, so heat from the combustion chamber is transferred straight to the coolant. This direct contact provides efficient heat removal and helps keep the bore temperature stable, which supports proper piston ring sealing and engine durability. A dry liner, by contrast, is not in contact with the coolant—the heat moves through the engine block instead, which is less effective for cooling the bore. Plastic liners aren’t used for this purpose in typical engines due to heat and chemical exposure, and metal liners can be either wet or dry, but the key distinction here is direct coolant contact, i.e., a wet liner.

When coolant contacts the cylinder bore directly, the liner is a wet liner. Wet liners are part of the cooling system and sit in the water jacket, so heat from the combustion chamber is transferred straight to the coolant. This direct contact provides efficient heat removal and helps keep the bore temperature stable, which supports proper piston ring sealing and engine durability. A dry liner, by contrast, is not in contact with the coolant—the heat moves through the engine block instead, which is less effective for cooling the bore. Plastic liners aren’t used for this purpose in typical engines due to heat and chemical exposure, and metal liners can be either wet or dry, but the key distinction here is direct coolant contact, i.e., a wet liner.