The maximum temperature that automotive coolant (antifreeze) can typically withstand depends on its composition and pressure system. Under normal operating conditions:
Standard ethylene glycol-based coolant can handle temperatures up to 129–135°C (265–275°F) when used in a pressurized cooling system.
Propylene glycol-based coolants have a similar or slightly lower boiling point.
With high-performance or extended-life coolants, the boiling point can be even higher when combined with a high-pressure radiator cap.
It's important to note that the pressurization of the cooling system raises the boiling point significantly. Without pressure, coolant would boil at around 100–108°C (212–226°F), depending on the mixture ratio.
