Subject:
Freeze Plug:
Freeze plugs are mounted on the outer wall of the engine. These are lightweight metal plates that seal holes in the internal cooling channels of the engine block. During the casting of the engine block, these holes hold internal molds in place, and after production, they are used to remove dust and grinding particles from the cooling channels. An additional advantage is that if the coolant freezes (when the antifreeze content is too low), these plates may freeze and break. This can protect the cooling channels from cracking, as the pressure from the frozen coolant finds its way out. This advantage is why they are called “freeze plugs.” However, it can still go wrong, and the block may crack due to freezing. This happens if the antifreeze content is much too low, or due to an extremely cold climate. See more information about antifreeze, also known as Ethylene Glycol.
The downside of a freeze plug is that they can sometimes leak. Coolant may leak out or mix with engine oil. Usually, they are quite easy to replace.
