What is freeze plug?

Freeze plugs, also known as expansion plugs or core plugs, are used in internal combustion engines to seal the holes left in the engine block after the sand casting process. They are typically made of metal, such as steel or brass, and are designed to prevent the coolant from leaking out of the engine block in the event of freezing temperatures.

Freeze plugs are located in various places on the engine block, such as on the side of the block, the rear of the block, and sometimes the cylinder heads. They are typically round or oval in shape and are installed by inserting them into the holes in the block and using a specialized tool to expand them to create a tight seal.

If a freeze plug fails or is damaged, it can lead to coolant leaks, engine overheating, and potentially catastrophic engine damage. It is important to regularly inspect freeze plugs for signs of corrosion, rust, or damage and replace them as needed to ensure the proper functioning of the engine cooling system.