Because when the cap is removed the liquid inside wants to start cooling itself. The heat energy is released by boiling.
When the radiator cap is removed, the pressure inside the radiator is released suddenly, causing the water to boil explosively due to the rapid decrease in pressure. The water in the radiator is under pressure to raise its boiling point, and when that pressure is suddenly relieved, the water can boil and turn to steam very quickly, leading to an explosive release of steam and hot water.
Water boils at 212F at Sea level pressure, 14.5 psi or so. If the pressure is increased, so is the boiling point. This is how a pressure cooker cooks with water at up to 500 degrees, and how a nuclear reactor can heat water to almost 3000 degrees, without boiling. Also, water will boil at room temperature or less, if you reduce the pressure, such as applying a vacuum pump to the container. When you open that radiator cap, it causes a drastic change in pressure, a drop. If the water is only warm, just under 200F, say, it will likely just boil violently. If it is above the normal boiling point, that pressure was all that was keeping it liquid. This violent change from liquid to gas is known as flashing. It changes states of matter, and releases a huge and violent amount of energy. This flash is what turns the turbines in power plants, by the way.
yes
just take the shroud off to give you a little bit of room to work leave the radiator in
Hydrogen burns explosively. That's why Lead Acid batteries are never tested for water level with live flame.
There is a drain plug on the oil pan that when removed you get oil, and a radiator drain plug that when removed you get antifreeze/water. The radiator drain plug is located at the bottom of the radiator (very front of engine compartment). Typically you can find it by reaching up behind the front bumper and feeling for a large-ish wingnut. They are usually plastic, about the size of a quarter or half-dollar, and can be removed by hand.
if its out of the top you might need a new cap they are pressurized and sometimes the spring is bad
No, it is very slow reaction.
The radiator on a 98 Buick Century is flushed by turning the petcock to drain the coolant. Water is then flushed through the system until all contaminants are removed.
Coolant leak, plugged radiator, failed water pump, inoperative fan.
The compound oxygen and hydrogen can combine explosively to form water.
there is supposed to be water in the radiator. your radiator is supposed to be evenly mix 50/50 with radiator fluid and water, preferably distilled water.