After the engine works, the cooling water is heated to nearly 90℃ or even higher.
After rising, the internal water vapor is covered by the water tank cover until the pressure exceeds the pressure relief threshold of the cover.
When the lid is opened when it is hot, the coolant will be sprayed out, and the high-temperature coolant will burn people around.
Very dangerous!
Try again when the car is completely cooled.
Moreover, loosen it a little bit very slowly first, and then loosen it a little bit if there is no problem. Loosen it once or twice before you can quickly loosen it.