What is the danger of removing the radiator or expansion tank cap when the engine is overheating?

Removing the radiator or expansion tank cap when the engine is overheating poses a significant risk due to the pressure that builds up in the cooling system. When an engine overheats, the coolant inside the system can reach very high temperatures, leading to increased pressure. If the cap is removed, this pressure can cause hot coolant and steam to burst out forcefully, which can result in serious burns to the person attempting to remove the cap.

Understanding the dangers related to overheating systems is crucial for safety. In high-pressure scenarios, the coolant can act almost like a geyser, leading not only to personal injury but also to potential damage to the vehicle's cooling system. It is important to allow the engine to cool down before attempting to open any components of the cooling system to avoid these hazardous situations.