What type of coolant is commonly used in modern vehicles?

Glycol-based antifreeze is widely used in modern vehicles due to its effective properties in regulating engine temperature and preventing freezing. This type of coolant typically consists of either ethylene glycol or propylene glycol, which have a low freezing point and high boiling point. This allows glycol-based antifreeze to perform well under a variety of temperatures, ensuring that the engine operates efficiently regardless of external conditions.

Additionally, glycol-based coolants provide corrosion inhibitors, which protect the engine and cooling system components from rust and other forms of degradation over time. The formulation is designed to be compatible with the materials used in modern engines and radiators, promoting long-term durability and performance.

In contrast, other coolant types listed aren't typically used in current vehicle designs. Water-based antifreeze, while it may seem logical, doesn't provide the necessary freeze protection or boiling point elevation on its own and usually requires additives to be effective. Glycerin-based antifreeze is less common for automotive applications, while oil-based coolants are not typically used in automotive cooling systems because they do not offer the necessary heat transfer characteristics and could introduce complications with the vehicle's engine management systems. Therefore, glycol-based antifreeze represents the industry standard for modern automotive applications.