Freeze Plug, also known as a Core Plug, Expansion Plug, or Cylinder Plug, is a round metal plug that is used in an engine's cylinder block, head, or manifold to help it maintain its shape under extreme temperatures. Freeze Plugs provide an internal seal between a piece of metal (e.g. a cylinder wall, head, or manifold) and a body of liquid (e.g. water) or gaseous fluid (e.g. steam), so that their expansion or contraction due to extreme temperatures won’t damage the metal.

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Generally made from brass or steel, Engine Freeze Plugs come in many shapes and sizes, with the most common variety being the round ones. These are installed in the cylinders, cylinder heads, and intake and exhaust manifolds of cars, motorcycles, and other machines with engines. They may also be used in mechanical devices like pumps and compressors.

To install an engine freeze plug, you must first determine the size and type of the plug, and then find and mark the location where you need to insert the plug. Pop out the old core plug (or drill it off if it’s frozen in place) and clean the area. When the area is clean, you can lubricate the inside of the hole and the outside of the core plug, then push the plug into place. Make sure to not force it, and ensure that the plug is installed properly and that the pl ed hole is completely sealed.

The primary function of a Freeze Plug is to protect an engine’s internal components from the harmful effects of extreme temperatures and pressure. They help maintain the stress balance on an engine and help to prevent problems like cracking or warping of the engine components. If the coolant or engine oil gets too hot, the plug will expand and prevent the engine from overheating, or equally, in the case of cold weather, the plug will contract and help prevent the engine from freezing.

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