What is freeze plug on engine?

Freeze plugs, also known as expansion plugs or core plugs, are small disc-shaped plugs made of brass or steel that are located on the engine block of an internal combustion engine. These plugs are designed to pop out if there is a sudden increase in pressure within the coolant system, which prevents the engine block from cracking due to the expansion of freezing coolant.

Freeze plugs are typically found on the side of the engine block and are easily accessible with the engine assembly removed. They are usually installed during the manufacturing process of the engine. Sometimes they may need replacing if they become rusty or corroded.

The size and number of freeze plugs vary depending on the engine size and type. Most engines typically have between four and six freeze plugs. It is essential to maintain proper coolant levels and keep the coolant system clean to prevent freezing and damage to the engine block. If a freeze plug pops out, it's important to replace it immediately to prevent coolant leaks and further engine damage.