Freeze Plug and Core Plug Replacement

When your vehicle’s engine is being assembled, sand casting cores are used to bore out the internal tubes and areas in the engine block where the pistons, valves and other parts will be installed. After the final assembly, these cores are used as the coolant lines in the engine, so that there aren’t any wasted open cavities in the engine that could lead to fracture or any other type of stress. To seal off the entry of these cores from the outside world, core plugs are used. Core plugs are a thin, domed disc of metal that is machine pressed into the opening to prevent anything from coming in or out. Freeze plugs are similar but serve a different purpose. They usually are holes placed on the side of the engine block to prevent damage from when water inside the engine block freezes and expands. Before the pressure becomes enough to crack the block, the freeze plugs will pop out and relieve the pressure on the engine block.