In the block, the oil spray tubes cool the

In the block, the oil spray tubes cool the

• A. Piston crown
• B. Underside of the piston
• C. Cylinder head
• D. Valve guides

Answer: (B)

Oil spray tubes are used to remove heat from the piston by directing cooling oil to the underside of the piston. The heat from combustion loads the piston crown, and that heat conducts through the piston body to the underside. Spraying oil there absorbs that heat as it flows back to the oil pan, keeping the piston cooler, reducing thermal stress, and helping prevent piston scuffing and wear. The cylinder head is cooled mainly by the coolant system, not oil spray jets. Valve guides are cooled by lubrication and other cooling methods, not by oil jets aimed at the piston underside.

Oil spray tubes are used to remove heat from the piston by directing cooling oil to the underside of the piston. The heat from combustion loads the piston crown, and that heat conducts through the piston body to the underside. Spraying oil there absorbs that heat as it flows back to the oil pan, keeping the piston cooler, reducing thermal stress, and helping prevent piston scuffing and wear. The cylinder head is cooled mainly by the coolant system, not oil spray jets. Valve guides are cooled by lubrication and other cooling methods, not by oil jets aimed at the piston underside.