Explaining a car on Instagram: "Resurfacing a cylinder head is the process of machining the head’s mating surface — the area that seals against the engine block — to restore perfect flatness and ensure a tight seal with the head gasket. Over time, heat cycles and pressure can warp or damage this surface, leading to compression loss, coolant leaks, or gasket failure. The resurfacing procedure involves removing a thin layer of metal (often just a few thousandths of an inch) using precision milling