How does antifreeze work in an engine?
SEED FAQ 1112 explains how adding soluble materials such as salt to water lowers the freezing point. In theory, anything that dissolves in water can be used as antifreeze, but in practice, there are several constraints. – the substance should dissolve easily in water at any concentration and not crystallize out at low temperatures. – it should be inert, so it does not react chemically with metal and other materials in the engine – it should be cheap – it should have a high boiling point, so as not to build pressure inside the engine. A very widely-used substance that meets these specifications is ethylene glycol, which has a boiling point of 387F (197C). A cooling system that has a 1:1 ratio between glycol and water has a freezing point of about -40F(-40C), which is ideal for the normal operating range for most applications.
